Google VP Marissa Mayer just announced customized search system Google Co-op.

What Mayer said at the live-streaming Google Press Day:

• Mayer: "You subscribe to people and organizations you think are interesting, who you want to collaborate with on search results."
• On top of search results, you might find a subscribe link. This works kind of like personalized results — if you subscribed to a site called Gapminder, relevant searches will put the Gapminder results at the top.
• Digg news is a Google partner! Good job, Kevin Rose! You are so worth more than Yahoo's $40 million offer.
• Five or six other partners — Fandango was one, missed the others.
• Marissa kids about Google Health, which she "accidentally" clearly leaked in an interview. So yeah, that's launched. Big surprise. But it does show a new, user-built form of vertical-building. Yep, even Google recognizes the occasional usefulness of humans.