Twitter calls Google (GOOG) a "good role model," but says it isn't ready to rush down the road to advertising.

Nonetheless, an ad-based revenue model is something that cofounder Biz Stone says they "will be looking to do down the line." But, for now, he continues, Twitter is focused on "creating value for our users." For now, revenue generation ideas are being put on paper, "and we're definitely going to get to them," Stone says.

Although I have a couple of different topics concerning the life of someone who travels frequently for work that I wanted to write about this week, my mind and heart are filled with thoughts and concerns for a good friend and his new baby girl. I've been waiting for weeks to get a status on his new baby girl, and this morning I heard that since her birth Monday night, she's been in the intensive care unit. As soon as I read the update, my heart began to ache, and my eyes started to tear. Now, I'm not the most sensitive person in the world, but the thought of my friend's baby girl struggling for her life just rips me apart.

Throughout our travels, we get the opportunity to meet more people than imaginable. Some people we would love to call a friend and see every day, and some we hope to never see again! Years ago (not that many years), it was easy to travel, work with customers or vendors, and bid farewell, never to see them again. However, in the days of LinkedIn and Facebook, the ability to maintain contact with a one-time introduction becomes as easy as catching up on the day's news.

Once upon a time, Mac users could brag they were much safer from malicious electronic attacks. After all, in the days before Google (GOOG), when Microsoft (MSFT) was the only uber-player in town, Windows was the perpetual malware target. Phishers, however, aren't discriminating; they're just looking for an account to plunge. So, both Apple (AAPL) and Microsoft users are threatened. Virus writers do tend to focus on the Windows operating system, which owns 90% of the OS market, but phishers are platform independent.

Phishing involves attempts to get a user to reveal information about their accounts. Once the soon-to-be victim clicks that link or fills out a form, the "transaction" is complete -- no operating system interaction necessary. As a result, there really isn't any advantage to using a Mac over a PC.

Company attitudes toward social media sites vary. Some swing the doors wide open, allowing employees to tend to their Facebook farms and update Twitter statuses throughout the day. Others lock 'em down, keeping non-business site access to a minimum.

A recent study found that, in the United States, 77% of employees with Facebook accounts check in with the community from the office. And, the amount of time they're spending in this part of the online world is growing. In the United Kingdom, another study found that 57% log in regularly from work, costing their employers 40 minutes a day.

Philip Wicks, a consultant at Morse PLC, a technology research firm in London, "It isn't just something you can do for half an hour during a lunch break but all through the day and because of that, it has a huge impact because people aren't necessarily concentrating on what they should be doing during the day." He estimates that this translates to lost productivity of $2.25 billion a year.

It seems like the obvious move would be to block the sites, but William Beers of PricewaterhouseCoopers disagrees. "Instead of trying to shut it down, I think we should try to embrace these technologies, put in a nice policy that governs it and explain to users the risks related to it, provide some training and then see what business benefits we can have from it," he said.

When I visited the offices of LinkedIn about six months ago, the place was frenetic with activity as the business networking site was in the midst of surging growth.

Investors wanted a piece of it, naturally, and indeed today LinkedIn announced a Series D funding of $22.7 million. The investors include a mix of VCs as well as strategics: Goldman Sachs (NYSE: GS), The McGraw-Hill Companies (NYSE: MHP), SAP Ventures (NYSE: SAP) and Bessemer Venture Partners.

The deal indicates that LinkedIn's growth prospects remain intact. After all, in the current tough economic environment, business networking is critical.

LinkedIn's investor roster also shows that the company is likely to expand into new categories. For example, with the support of SAP, LinkedIn can make inroads into on-demand enterprise computing.

Dan Nye, who is the CEO of LinkedIn, wrote this in his blog:

"I'd like to reiterate our commitment to creating the right partnerships to help us build a great service for over 30 million professionals on LinkedIn today - a number that's growing by leaps and bounds each month. This funding strengthens LinkedIn further, and will help us to continue creating additional services for professionals to connect and collaborate more effectively, around the world. Services that allow you to connect with the people you trust, build out a robust online professional profile and collaborate with members of your professional network on LinkedIn."

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Streetsmart Guide to Short Selling: Techniques the Pros Use to Profit in Any Market. He is also the founder of BizEquity, a valuation website.

First the New York Times (NYSE:NYT), and now CNBC are beating the targeted advertising drum by entering into tie-ins with LinkedIn, according to FT.com.

This gives CNBC a way to enter into the world of professional networking and illustrates the growing importance in advertising of niche online communities. But it also raises privacy concerns for the professional network. Naturally, CNBC would love to gets its hands on the LinkedIn community; but does the Linked community want CNBC? Dan Nye, LinkedIn's cheif executive, said the current agreement doesn't allow CNBC to get member profiles now, but may in the future.

Nye told FT that its advertising revenues had grown by a whopping 300 percent on year.. Because of the Bain Capital-led venture capital cash infusion in June of $53 million, LinkedIn is now valued at over $1 billion.

From some of the companies I've talked to, the results from advertising on LinkedIn have been fairly strong. Then again, the website is the largest and fastest growing professional network, making it much easier for targeting.

Well, LinkedIn is improving things even more. That is, the company has launched LinkedIn DirectAds. As the name implies, this is a self-service system.

Of course, this may not be the best option for major advertisers that need sophisticated campaigns. But, for small companies, this solution can be ideal (hey, just look at the success of Google AdWords).

And the targeting for DirectAds is highly granular. For example, you can select a myriad of industry categories, such as CPAs, graphic designers, and so on. Or, perhaps you want to focus on sales executives or CEOs? Keep in mind that LinkedIn has 20 million registered users (with extensive profile information on each).

Getting started is easy. The process takes a few minutes and the minimum fee is $25.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates MergerBook.com.

This post is part of my series featuring established companies and the smaller, more aggressive or innovative rivals that may eventually succeed them.

I remember way, way back to November 2006 when Wall Street was stunned that Google (NASDAQ:GOOG) was paying the ungodly sum of $1.65 billion for privately held YouTube. How were they to monetize this goofy, home video web site? Since November 2006, it appears that Google got a bargain when compared to other social networking web sites.

Facebook has over 80 million users including a new Facebook profile for Democratic presidential nominee Barack Obama. Facebook attained Wall Street relevancy last year when Microsoft (NASDAQ: MSFT) agreed to pay the unheard of $246 million for a 1.6% ownership stake. That October 24, 2007, Microsoft investment valued Facebook at nearly $10 billion in the private equity world. As of yet, there is no filed Facebook IPO, but investors bet the company will file an IPO before the end of 2009.

The new player capturing headlines in the social networking world is LinkedIn. The company is designed for the business and professional world. The more than 23 million registered users represent over 150 different industries. It's a place to swap ideas, best practices and other opportunities.

I recently saw a presentation from Dan Nye, who is the CEO of LinkedIn. Of course, all the metrics were spiking. Then again, LinkedIn is the place for professionals to connect.

So, this week the firm has snagged $53 million in venture capital. The investors include Bain Capital Ventures, Sequoia Capital, Greylock Partners, and Bessemer Ventures. As a sign of their optimism, the valuation of the investment came to around $1 billion.

While Facebook and MySpace get lots of buzz, I think LinkedIn is a more interesting play. Basically, the company is leveraging user-generated content to build an immensely valuable database. For example, if an advertiser wants to target someone located in California that is interested in Linux systems, you will definitely get some hits. This is critically important. After all, many other social networks have a tough time monetizing things.

Who am I? I'm wondering after having been utterly unable to log in to my very-long-time LinkedIn account using my own email addresses (all of which feature the words "sarah" and "gilbert" prominently). While it's true I keep no extraordinarily private data in my account profile (the fields for "social security number" and "mother's maiden name" aren't yet a feature of the social networking site that's been valued at $1 billion), still, when I discovered that a complete stranger was accessing my account using her own very different email address (her first name is "Kristin" and we have a few friends in common, but absolutely nothing else), I was rattled. This is both bizarre and troubling.

She found my email address through one of our common friends, and sweetly sent me her password, so I could actually be me for a bit. I approved a couple of pending connection requests. I sent an urgent, full-of-exclamation-points email to LinkedIn. [As of mid-afternoon on May 27th, I've still heard nothing from LinkedIn, and a scan of recent Twitter messages showed scattered problems.] I asked my friends if they'd heard of anything like this, and found one similar problem (as far as I can tell, it was unresolved). I'm so fortunate that it was a friendly connection and not someone bent on masquerading as me (which could have ranged in dangerousness from the mild -- wildly recommending people I don't care for, maybe -- to the seriously fraudulent). What if Bill Gates had his identity gifted to someone else? Salacious, no?

However mild or serious the result of this security breach, it's not something to be taken lightly; and a bug like this could turn off professional users who trust LinkedIn with their resume; it's certainly not befitting a billion-dollar company built on the concept of identity. News Corp., are you still interested?

LinkedIn has become a great tool to help improve your business. For example, Brant Bukowsky, the founder of LakeRentals.com, used the online service to locate a prospect for a management buyout. Or take MyBlogLog. The company found its CEO with LinkedIn and a year later, the company sold to Yahoo! (NASDAQ: YHOO);

So, how can you use LinkedIn for your business?

Well, I recently had a chance to meet up with Allen Blue, the Vice President of Product Strategy of LinkedIn and the company's co-founder.

In fact, he provided a framework on how to use LinkedIn. Let's take a look:

Microsoft (Nasdaq: MSFT) loves social networking. No doubt, the company thinks there's a potential goldmine there.

Hey, the firm recently invested $240 million in Facebook -- at a whopping $15 billion valuation. In fact, Bill Gates even setup a public profile on the social network. But there was a problem; that is, too many people wanted to be his friend. Bill was actually getting about 8,000 requests per day.

As a result, he shut down his profile.

Well, Bill hasn't given up. He's now going to go on LinkedIn and answer questions regarding his philanthropic efforts (this is according to a story in C/NET).

To me, LinkedIn's Q&A feature is great (I've even used it to get sources for my stories). Although, as for Bill, I'm sure there will be a flood of questions. Keep in mind that LinkedIn has 19 million registered users.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates DealProfiles.com.

For the tech business people I know, there are two "must haves:" a BlackBerry -- Research in Motion (NASDAQ: RIMM)'s smartphone -- and a profile on LinkedIn, a social network that has 19 million members.

But, interestingly enough, the two systems haven't been able to talk to each other – that is, until now.

Today, LinkedIn has launched a mobile version of its service. In fact, not only can you use it with your BlackBerry, but also on Apple (NASDAQ: AAPL)'s iPhone as well as other devices.

What's more, LinkedIn has added language support for English, French, German, Spanish, Japanese and Chinese.

However, the mobile edition is in the beta phase and as a result, the feature set is somewhat limited. For example, you can't accept an invitation or even update your profile. Yet, I'm sure LinkedIn will continue to evolve the product and get a sense of user behavior over time -- which has been a hallmark of the company over the years.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates DealProfiles.com.

I'm a big fan of LinkedIn, which is a social network for professionals. In fact, the service has helped me get sources for some of my stories.

But competition is starting to emerge, the latest comes from Hoover's, a part of Dun & Bradstreet (NYSE: DNB). Hoover's has acquired Visible Path, which develops an enetrprise-class social networking platform.

So what makes Hoover's Connect different? Essentially, it's a LinkedIn for individual companies and the system integrates with Microsoft (NASDAQ: MSFT)'s Outlook and other products.

Perhaps the biggest key, however, is privacy. After all, if you are a major executive (who has the power of the checkbook), do you want your contact information freely available?

Hoover's can also leverage its large base of business customers. For example, it is possible to use the system to develop referral paths for various companies, making it to make it easier to make a connection. Actually, according to a study from the University of Chicago and University of North Carolina business schools, it is 16 times more likely to get a response from a trusted source versus a cold call.

Tom Taulli is the author of various books, including The Complete M&A Handbook. He also operates DealProfiles.com.

News Corp. (NYSE: NWS) reportedly is in talks to buy social networking site LinkedIn.

"A well-placed source has confirmed with us that these talks are serious," writes VentureBeat's Eric Eldon. "News Corp.'s strategy, from what we understand: Somehow integrate LinkedIn's network with the Wall Street Journal as well as its other newspapers around the world, hopefully figuring out how to recoup News Corp.'s newspapers' declining classified ad revenue in the process."

The strategy makes sense. Plus, Murdoch is eager to bolster the company's social networking business in the face of the rising popularity of MySpace. LinkedIn claims that 14 million professionals use it, representing every member of the Fortune 500. Its investors include Sequoia Capital, Greylock, the European Founders Fund and Bessemer Venture Partners.

As Murdoch has shown with the $5 billion acquisition of Dow Jones & Co. (NYSE: DJ), Murdoch is willing to pay up for something he wants and if shareholders benefit so much the better. Investors continue to be sour on the media sector and will be for a while considering the uncertainty surrounding advertising spending and the overall economy. Shares of News Corp., which recently said earnings were rising ahead of its forecasts, are down 3% this year.