LazyWeb: Next Gen Aggregation

So, I have a couple of news feeds that collect recent blog posts about Knowledge Management (PubSub and Feedster) or that might be similar to my blog (Waypath).

However, I get a heck of a lot of repeats with the blogs that I already read. What I'd love is a way to give them my OPML file and tell them to ignore anything that I will already see anyway. In other words, I just want the new stuff. Does that exist yet?

Roland Tanglao gives some advice "The Lazy Person's Guide to being a Newsmaster, Part 1." And someone else recently talked about getting rid of their blogroll in favor of well-designed searches with RSS feeds. Interesting idea.