Comments should be searchable. I should be able to aggregate all comments I or someone else has left on a particular blog. Ideally, this should span the entire blogosphere so that I could aggregate all the comments I have left on all blogs. It would be easy, then to see where people go and what they say. This way the audience of the blogosphere would be much more empowered. In essence, I wouldn't necessarily have to start my own blog to, in effect, have a blog of sorts.
The reason I personally would like searchable comments is because I've spent a lot of time and energy posting to other people's blogs. Pieces of my writing are floating around out there in the blogosphere, and it occurred to me that it would be nice if some how I could get it all back. Thinking about it some more, I concluded that it would be good for the common weal of the blogosphere because by allowing a particular person's thoughts to be traceable through the blogosphere, a clearer, more nuanced picture of an individual would emerge than would be possible by just looking at the comments posted to one or two blogs. The blogosphere audience would come alive, so to speak.
By allowing searchable comments the blogger and the audience would be placed on almost equal footing. In fact, it would almost make them one in the same thing: my blog could simply be an aggregation of all that I've posted on other people's blogs. Anyone looking at such a blog would see a link to the blog where the comment was first posted thereby reinforcing the whole blog idea. I think all of this would give people a much greater incentive than they know have to participate in blogging by writing comments and sharing thoughts. In fact I'm certain of it. As it is, I've noticed that people don't post that many comments. There are exceptions to this, but as a general rule it holds. By addressing this, the blogosphere becomes twice what it currently is.