I would have sworn I've already written about this, so if you've read it I apologize.
A few months ago
my friend Scott posted this: "Follow = RSS + Humanity, so the commercial opportunity is far richer." (Just to give some context to Scott and his RSS creds, we met when I
interviewed him for an article on RSS in 2004.)
Anyway, was thinking about this a little more recently, especially as I've gotten
more into Tumblr and I think it's super insightful plus a signal of a larger trend that's going on. RSS was never destined for mainstream in it's current form because it just takes too much work. Lots of browsers have tried to make it a little easier with live bookmarks and what not, but ultimately it requires new mechanisms to really reach the masses. In the end I wonder if the biggest takeaway from Twitter/Tumblr will end up be this humanizing of the technology.