Yahoo has a Yahoo Mail API prototype but no open protocol yet beyond what it offers for premium Yahoo Mail subscribers. Microsoft March 25 unveiled a Windows Live Contacts API to let contacts between different social networks sites such as LinkedIn and Hi5. Marashi expects that other mail platform providers "imminently will become more enlightened and understand that third-party application developers can engage their users on their site and make the experience much better."While Marashi is wishing and hoping for these universally open platforms, Yahoo is busy with its own Inbox 2.0 vision for Yahoo Mail. The company this year will launch OneConnect, a suite that includes a social address book to let users access their MySpace or LinkedIn accounts from their address books.Like Xoopit and Xobni, the software will allow users to view status updates, photo uploads and the recent activity of contacts across their networks. Forrester Research analyst Charlene Li and other analysts are also discussing the notion of e-mail inboxes as the starting points for social networks. "The idea that your inbox would be highly socialized is very valid," Li told eWEEK April 1. "The key thing is pulling out attachments, and identifying a JPEG, GIF, or a video, and putting it into a central place. It takes out a lot of the friction that is associated with social media today, especially if one of the key ways you get your content is via e-mail." Xoopit, Xobni and Yahoo are all hewing to this notion, but will they realize their goals? Xobni and Xoopit currently offer their services free, but both expect to make money from ad generation similar to the way Google does with e-mail. Both expect third-party programmers to jump on board to build out their respective tools. However, TechCrunch claims Xobni is a target for acquisition by Microsoft, which makes sense because such as tool would save Microsoft the time and trouble of building it themselves. And since Xoopit is tailored for Google's Gmail, we might expect the same rumors to burble up if Xoopit gains momentum. Acquisitions of Xobni and Xoopit by Microsoft and Google, respectively, would give those rivals the social inbox firepower to meet Yahoo head on. The space bears watching.