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."

With close to 60 million users, Twitter is a force corporate marketing departments just can't ignore. The reach offered by this microblogging platform is profound, and skipping it means yielding digital turf to the competition.

Yet, as the country's major brands have flocked to Twitter, not all have mastered it. Some merely push headlines and deals, while others have used it as a way to open a dialogue with their customers, build relationships and ultimately grow their businesses. A study by The Big Money sought to determine the dozen companies that are mastering Twitter and why they are the masters.

Twitter is on the prowl. Though it made its last acquisition more than a year ago, company founder Biz Stone said on Tuesday that it's looking to add to the stable. There aren't any specific targets yet -- at least none revealed -- and Twitter is keeping its options open. The likely pool of potential acquisitions consists of third-party Twitter application developers, which is largely responsible for the micro-blogging service's growth in popularity.

Stone, one of Twitter's founders, said at a Tel Aviv news conference, "As our attention is grabbed by some of these developers, we will take a hard look at them." This refers to companies that develop applications for Apple's (AAPL) iPhone and Research in Motion's (RIMM) Blackberry. It also refers to developers for the Web and desktop, such as HootSuite and TweetDeck.

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.

Seemingly out of nowhere, Twitter has turned into a huge phenomenon. I hear about it all the time. In fact, it's an extremely easy service -- basically, think of it as public instant messaging.

Oh, and there's something else: Twitter doesn't make any money.

But hey, it doesn't so much matter (at least now). You see, the company has raised $35 million from Benchmark, Union Square Ventures and Spark Capital Institutional Venture Partners. It's the company's third round of funding. Moreover, the rumor is that the valuation is now at $200 million to $250 million.