In talking with a colleague, I discovered that he has over 700 web feeds, and that he makes heavy use of blog search feeds to highlight topics in which he has particular interest. Given that I am now at over 300 feeds, including about a dozen search feeds, I imagine that he has even more trouble than I keeping up with everything. I generally browse searches last, but I am not particularly interested in seeing results for articles I've already got in my normal subscriptions.
I think the next generation of aggregators / rss readers needs to be better at managing this kind of situation. Just like the threading available in aggregators like RSS Bandit and SharpReader (new version just came out), I would like to see my aggregator remove (or ignore) items from the search feed that are already available in my other subscriptions. Or maybe I'd want it the other way around: read the searches first and then my feeds, but without the things that have already come through on the searches.
There are technical issues with this, since each blog search tool has a slightly different results format, most with a click-through setup to gauge their traffic. But there are plenty of smart people out there who should be able to figure this out.
Let me know when you've figured this out, okay?