Google Health has been widely anticipated in the past couple of weeks. After yesterday's press day at Google, the reaction to Google Health seems to have cooled, perhaps because it was introduced as part of a new program at Google called Google Co-op. Instead of the approach taken with Google Scholar or Google Finance, where Google staff choose sites to crawl for inclusion in the specialty search areas, Google Health will be a cooperative project between product architects at Google, authoritative sites selected by Google, and content tagged by interested individuals, businesses, and organizations. The latter categories of content "contributors" will earn higher relevancy rankings if sufficient number of people subscribe to that contributor's collection of labeled webpages.

Google Health comes out of the gate with seven "significant" providers whose content is being tagged by health professionals. They include the National Library of Medicine, Centers for Disease Control, Health on the Net Foundation, Harvard Medical School, Mayo Clinic, U. California, San Francisco, and Kaiser Permanente.

Co-op verticals are a clever means of providing an incentive for publishers in the hottest topic areas to add consistent tags to their content to improve the relevance of search. It is too early to gauge whether this approach will work. There are some questions about ease of tagging (see Danny Sullivan's review in Search Engine Watch). Nonetheless, this approach has the benefit of adding depth and an added level of relevancy to main search engine results; providing a targeted experience for users who want authoritative information on health topics; and providing a means for knowledgeable insiders and publishers to raise their profile via votes of confidences in the form of subscribers to their labeled webpages.

In essence, Google Co-op allows users to build their own list of favorites to rank as most relevant for a topic via subscribing to the sources listed in the directory as well as supplemental sources of labeled content. To reach its full potential, the ease with which individuals will be able to use the tools to become contributors to create their custom view of relevancy will be perhaps most important to the success of the co-op approach to vertical search.