Billionaire investor Carl C. Icahn intends to move ahead with plans for a proxy fight at Web giant Yahoo, sources tell The New York Times. Icahn will propose a full slate of ten replacements to the company's board at Yahoo's next shareholder meeting in July. Today is the deadline for nominating a dissident slate. According to the Times, Icahn wants to restart talks about a possible sale to Microsoft, although Microsoft has given no indication that it's still interested. Analysts said Icahn's decision to try and oust the entire Yahoo board is a risky one, adding that he might …

Plaxo has finally sold itself, after months of rumors, but not to Google or Facebook. Rather surprisingly (err, curiously) Comcast Corp. has swooped in to acquire the social address book organizer. VentureBeat points out that Comcast and Plaxo already had an existing partnership, so the cable distributor must have thought the time was right to take the relationship to the next step. But VB said that Plaxo didn't come cheap, costing somewhere in the neighborhood of $150 to $170 million. Plaxo's technology allows users to sync their contacts across email applications. Last year, the company added a new Facebook-esque …

Google co-founder Sergey Brin said that advertising on social networks like MySpace and Facebook is getting better. "In general, it's been improving but we still have a long way to go," Brin told reporters at a conference in Jerusalem marking Israel's 60th anniversary. "Things have been going well this year...it's hard to predict where social networking will come out." Brin said it would take time to develop the right formula for advertising on social networks. "People are expecting overnight to wake up to a miracle... but these things take time," he said. In January Google CEO Eric Schmidt said …

Nobody's up in arms yet, but Fortune writer Jesse Hempel said that CEO Mark Zuckerberg is starting to take hits from Facebook users, developers and advertisers. Unrest amongst your entire constituency usually presages the end for a public figure or company CEO, but Facebook is private, with aspirations of eventually going public. In many ways, Hempel suggests that this is Zuckerberg's most trying time as CEO. The past two years have been a period of phenomenal growth for Facebook, doubling 12 times over since September 2006, when Zuckerberg opened the site to non-students. The Facebook Platform six months later was …

In a blog post last week, Facebook developer Jesse Farmer declared that the Facebook Platform Party is over, citing a 27% decline in activity in the developer forum since January, a decline in overall postings of 51% over the same time period, and his finding that the average application launched in early January was 1.5 times more successful in terms of its adoption rate than ones launched in March. Meanwhile, Farmer pointed out that there are now many more destinations for social applications, from gaming sites to initiatives like Google's OpenSocial that broaden their reach, so developers no longer feel …

If you've ever wondered why Microsoft, with its $277 billion market cap, is so worried about Google, Silicon Alley Insider's Henry Blodget has some interesting statistics to show you. By early next year, he said that Google's search business (excluding contextual revenue from AdSense) will surpass that of Microsoft's Windows. Of course, when you add Office (Microsoft's other massive monopoly that usually comes bundled with Windows) to the equation, that gap remains large. According to SAI, Google did around $3.5 billion in search revenue in the first quarter compared to almost $9 billion for Windows and Office combined. It …