As much as I love Twitter (you can follow me here), and A-list bloggers constantly bang on about FriendFreed, Facebook will be the one to take lifestreaming mainstream.
In fact, in someways it already has.
The once controversial News Feed has already evolved to include aggregated activity updates from outside web services. The pending launch of 'Facebook Connect' aims to make this feature ubiquitous by creating a simple way for third-party sites to send a users' online activities back to Facebook's proverbial brain.
While the newly launched 'Live Feed' provides a real-time view of Facebook's lifestreaming data, whereby the latest friend update fades in AJAX-style and pushes the oldest update off the screen (not dissimilar to Digg's Spy feature). It makes compelling viewing of all of your friends' lifestream activity and certainly brings the concept of lifestreaming even further to the forefront of Facebook's functionality.
See also: Powering Facebook’s proverbial brain: your Identity, Social Graph, and Lifestream data
As Harrison Hoffman notes over at CNET, Facebook continues to add or build on features offered by both Twitter and Facebook, leading some to suggest that Facebook is about to eat their lunch.
"It's no secret that Facebook has been pushing its microblogging and life-streaming features to the forefront of the site recently. Facebook's 'What are you doing right now?' feature is extremely similar to Twitter and its commenting system for news items is very reminiscent of FriendFeed", writes Hoffman.
Of the two services, Twitter and FriendFeed, I'd suggest that FriendFeed has the most to lose as Facebook continues to encroach on the lifestreaming space. Twitter, despite its well documented stability issues, has a very vibrant ecosystem of its own, supported by a plethora of third-party applications and services via its public API. And since Twitter is first and foremost a micro-blogging service (as well as a communication platform), it can happily co-exist with Facebook's lifestreaming ambitions. A user's 'tweets' can be pulled into Facebook without taking away from Twitter itself.
FriendFeed on the other hand doesn't really complement Facebook's lifestreaming functionality but competes directly against it. That maybe just fine for social web power users who'll value the particular demographic and unique discussions taking place over at FriendFeed, but for the majority of Facebook's 100 million users, the site's own lifestreaming functionality will surely suffice.