RSS - does it do enough?

When I worked in information publishing, I was an avid user of our proprietary clipping service. Essentially, we could set up searches that would run at intervals we defined and receive a feed of updated material on my employer’s vast information databases that met the search criteria. For example, if I wanted to keep tabs on one of my products, I’d set a clip up with its name and every time its name was mentioned in the press, scholarly journals, etc., it would save a link to the content, aggregate all the links over my defined time period (usually one week) and send them via a concise email. I don’t work there anymore so this would be insanely expensive to continue (our customers pay by the search -- I didn’t know how good I had it!).

I wonder if there is a tool that works similarly for Blogs. That is a tool I’d definitely be all over. Maybe it exists in an RSS feeder, and I’m just not a sophisticated user. Please let me know if it does. This dream tool would run a search across all blog postings (not just for the ones I follow) looking for those that meet my search criteria. For example, let’s pretend that I was doing research on Web 2.0 teaching ideas. I could set up a blog clip that searches all educator blogs for “Web 2.0” and then probably a bunch of Web 2.0 tool names just to be sure I catch everything. This might help lead me to other blogs out there that I don’t even know I should be following.

If we were able to help students set something like this up to support them in their own research (and also maintain their safety), I think it would be easier to say which AASL standards it wouldn’t support than it would to identify the ones that it does.

Does this blog searching tool already exist?