LOUIS GRAY.COM — Thing Labs, the parent company of Brizzly, one of the more innovative Twitter Web clients out there, unveiled a slew of announcements this morning, with the acquisition of popular iPhone application Birdfeed and WikiRank, a visualization Web app based on Wikipedia data. The acquisitions will help fuel the launch of Brizzly's first branded iPhone application, and a new Brizzly Guide, which extends the trend explanations core to Brizzly since the product debuted with permanent definitions, accessible even after a topic stops trending...

TECHCRUNCH — Email marketing software giant ExactTarget has agreed to acquired CoTweet, a young company that offers a tool that enables multiple people to communicate on Twitter through corporate accounts. CoTweet will continue to operate from San Francisco as a business unit of ExactTarget, essentially taking charge of the company’s social media product development...

CLICKZ — LifeStreet Media, a social media ad network, announced last week that it will acquire its chief competitor, SocialCash. Both LifeStreet, which is based in San Carlos, Calif., and SocialCash, based in San Francisco, operate ad networks that serve ads almost exclusively to Facebook apps. LifeStreet launched its network in late 2008 and achieved a run rate of more than $40 million by the end of 2009, and claims an audience of more than 100 million globally, according to CEO Mitchell Weisman...

TECHCRUNCH — Google has acquired social search service Aardvark, says a source that has been briefed on the deal, for around $50 million. We first reported on the discussions between the two companies in December. Those discussions have now turned into a signed deal, says our source, and will be announced today or tomorrow. Aardvark, founded by ex-Googlers, has raised around $6 million in venture capital to date. The service let’s users ask questions and get immediate responses from their friends and friends of friends...

PAIDCONTENT.ORG — Zynga, the current social gaming behemoth, is using some of its money to do acquisitions: it has bought Serious Business, creators of social games on Facebook.  SB, based in San Francisco, and backed by Lightspeed Venture Partners ($4 million in funding), was founded in early 2008 by two former Powerset engineers. It launched one of the first ever games on Facebook, Friends For Sale...