Google (GOOG), which competes with Microsoft (MSFT), Yahoo! (YHOO), Aol (AOL) and Facebook in the search advertising market, has been working to increase its penetration in social networking. It started with Google's foray into social applications like Google Wave and Buzz, which did not meet initial expectations. Google then made a number of acquisitions for the development of its major upcoming social networking project named Google Me.

When Twitter announced its search-based advertising model, little more than a Google (GOOG) knockoff, the market yawned. It didn't seem like much after months and months of speculation, not to mention Twitter's promises that this was something "we would love and would be awesome."

Now, the details are out, and it could be more interesting than expected. On Twitter's blog, Biz Stone lays out "Promoted Tweets," ending the jokes such as Stephen Colbert's, "So, I assume that 'Biz' in 'Biz Stone' does not stand for 'Business Model."

Twitter's new look won't be limited to the redesigned Twitter home page. Doug Bowman, creative director at the social media company, posted a screen shot of a refreshed design for Twitter Thursday, according to SocialTimes. Of course, the whole screen isn't even shown because, as Bowman wrote in a comment, "Working on what may end up a significant redesign. Not final yet. What we can show without giving away the farm."

It looks like quite a bit is going to change, and as usual, even the smallest of updates could carry a significant revenue implication for Twitter. Here are four implications of a screen redesign for Twitter (and, more important, its investors):

Last year, Twitter said it had two goals for 2010: generate revenue and make acquisitions. At the time, the company was still sitting on a significant portion of its last round of capital, and given the $20 million annual burn rate revealed late last year -- plus the revenue it's generating -- it's unlikely that Twitter has had to deplete its coffers. So, Twitter has cash to put to work, and now we're seeing what that means.

On its blog, Twitter announced Friday that it has entered into an agreement with Atebits (aka Loren Brichter) to acquire Tweetie, which is one of the top Twitter clients for the Apple (AAPL) iPhone. In addition to acquiring the application, Twitter is also picking up talent. Brichter's efforts were good for a 2009 Apple Design Award, and he'll be part of future efforts to get Twitter for the iPad off the ground.

More than half of Twitter's users aren't from the U.S. Matt Sanford, lead engineer or the company's international team, writes on Twitter's blog that 60% of its user base comes from outside the U.S. This reflects steady growth from June 2009, when just over 55% of Twitter's users were domestic.

Big-name advocates in foreign countries have bolstered technical developments, such as the release of the platform in Spanish, with Colombian registrations up 300%. Those in India are gaining close to 100% thanks to adoption by high-profile politicians. Further, overseas partnerships, like the one with Bharti Airtel, have made Twitter viable overseas. Early on, international growth prospects were a concern, given mobile carrier rates and texting charges.

Twenty-six percent of businesses using Twitter say they'd pay for the right services, and that might just be good enough.

WebBizIdeas.com polled 850 Twitter business users about what services would lead them to pry open their wallets. Three quarters of them said they either weren't crazy or were unsure about paying for additional features like analytics (31% and 43%, respectively), which sounds like a menacing amount. Yet, the size of this social media environment may make the 26% sufficient.

Twitter may say that a new, redesigned home page reflects an attempt to provide more immediate visibility into what's happening on Twitter... but it's really a revenue play.

The new home page does a great job of providing the information hooks that would get a prospective user to click to learn more and ultimately open an account. Its clear objective is to increase the user base, a challenge that Twitter faced in the second half of 2009, after experiencing explosive growth in the two preceding quarters.

More users means more traffic. More traffic means more revenue.

Speculation about the future valuations of companies like LinkedIn, Facebook and Twitter has undoubtedly driven interest in private markets where early shareholders can turn for a taste of liquidity before the big day. SharesPost, which has been a source of information on the likely IPO implications of these companies, has been among the beneficiaries: membership has doubled ... since November. According to a statement by SharesPost, "over 15,000 buyers and sellers of private equity" belong to the site.