Google launched Google Co-op late last night, a service to create custom search engines. The central feature is that it prioritizes or restricts search results based on websites and pages that you specify. It also allows one to tag sources and to provide a way to focus on hits from sources with a given tag from the results page. You can open up the development and maintenance of your custom search engine to others, allowing people (everyone or just those you invite) to add or exclude sites and to tag sources.
Although Elias Torres beat us to it, we’re experimenting with the service with a Co-op search engine (here) that draws on a number of sites related to the semantic web. Feel free to add to it or tag some resources.
This is a good idea, though not novel — remember the concept of a focused search engine? The idea of letting users create their own focused search engines through a web interface is also not new. Rollyo is a Yahoo-powered service that offers the same basic capability and Swicki is another that offers some interesting wiki-inspired features. Google’s collaboration model is different though. I wish there were something between “anyone” and “invited individuals” for collaboration. The former opens the door to web spam, which will soon come in. The latter is too simple a model for building a large community. Update: After trying the collaboration a bit, I see that the “anyone” model requires the approval of the owner, so the collaboration model is reasonable, though simple.