Steve Gillmor believes that Twitter is the communications medium of the future. Send out a message to your followers and track (when the feature is enabled) the loosely coupled conversation as it wafts deeper into the cloud. FriendFeed, on the other hand, aggregates feeds from Twitter and many other sources, creating an index of the content (gestures in Gillmorspeak) an individual chooses to share with followers.
Twitter's friendly API allows applications to be built on top of it (when the site is up), letting FriendFeed and other services tap into the Twitter stream. In addition, FriendFeed allows users to comment on the contents of the aggregated feeds and has "rooms" for discussions among a group of people.
Steve Gillmor makes the claim that Twitter is being strangled by FriendFeed and that his pal Robert Scoble is hijacking the conversation away from the unreliable Twitter site to FriendFeed. It's much ado about nothing. Users have the freedom to head to their communications medium of choice. The Twitter conversation stream isn't locked into a walled garden--tweets can flow like water into applications such as FriendFeed, Summize, and Facebook.
It's not clear precisely where this latest twist on instant messaging and feed aggregation is heading, but just let it evolve without the prejudice in its own Darwinian way. That doesn't mean to back away from criticism or debate, but to do so in the context of open networks that provide ways for individual users and groups to shape their online experience.