That's a question I always think about: how to cope with a too large number of RSS feeds? Roland Tanglao answers:

here's how I plan on eliminating my RSS information overload: Subscribe only to 150 blogs at the most. These 150 will be people not search feeds from PubSub, Feedster, etc. and I will read them every day or at least try to. And I will update this list and add and remove people at least once a month. This group I will call MUSTS.

For the companies and blogs that I write, I will create PubSub and Feedster feeds for these companies' and blogs' keywords as well as RSS feeds for links to their URLs. This will be called WORK. I intend to keep this list to 100 feeds or less.

The rest (over 500!) will go into NICE TO READ and I will set them to the items to auto-expire so that if I don't read them for 24 hours, they are deleted. And if I find something in a NICE TO READ consistently, then I will promote it to MUSTS.

Of course, as he claims, "There's no need to read everything". I tend to think about this as the first rule. The first month I used a news aggregator I used to read everything and then I noticed that being updated is not a matter of reading stuff once in a while. It is rather to read a bit on a regular basis.

Another thing important is the notion of node, some people can keep track of stuff you're interested in but you don't have time to browse about. For instance, even though I am interested in blogs and syndication I don't really check website about it. Instead of reading specialized blogs on KM or blogs, I aggregate 2-3 of great blogs about it.