Google Co-op is a service you may have heard a bit about, and may have simply overlooked... I know I did at first. The idea is that you can give it a list of sites that have information pertaining to a very specific subject, and create a little search engine based on only those sites, filtering out everything else.

At first this seems like a bit of a parlor trick, but it's actually a very powerful concept and one that can be exploited in a number of ways, like this: Why not use Google Co-op to create your own personal search engine that only searches sites that you have subscribed to in a feed reader?

Google Operating System offers the instructions, and they are blessedly short. Here they are, in essence:

1. Get a local OPML file containing your subscriptions
2. Create a new Google Co-op search engine, and use a bogus site or two when it asks for what sites to search
3. Go to the Advanced section of the Control Panel for the new search engine you've created and upload your OPML file
4. That's it. You might want to remove your bogus URL at this point.

Google Operating System also offers a number of ways to make it easy to access your new personalized blog search engine.