Feeds and Blogs
This is an interesting post from Fred Wilson at A VC. Among other things, he supposes that in a year or two, feeds and blogs will start looking more alike.
I think the merging will be rss feeds and emails. Fundamentally, they are both means of one way communication, while blogs are an interactive interface.
My NetNewsWire already looks very much like my Mac Mail interface. And there's functional difference on MySpace, between sending/receiving messages and sending/receiving bulletins.
Not only do I think the interfaces will merge, but I can see the technologies merging somewhat, with RSS making your email workflow even more seamless than it already is.
By the way, I know I link to A VC a lot. That's because Fred has a really good blog.