I would argue with the assertion that he doesn't look at other products when evaluating Facebook. Its clear they've been copying from Twitter and FriendFeed for years, so I don't know where the Boz is getting that from.
He had the same idea as Twitter, some time before it launched. His version involved aggregating AOL Instant Messenger away messages--and that's the closest thing to Twitter, before Twitter.
I had that idea too, and so did thousands of other people. Twitter is the one who executed on that idea.