Photo licensed as Creative Commons by Google Blogoscoped.
Last month, Google started to test a new way to present search results that groups the pages by category and displays the top two results from each category. For example, if you search for a movie, you could see reviews, news, blogs, encyclopedia pages, stores. Each category can be expanded.
Google already shows refinements for a small list of topics like: health, computer games, travel, cars and photo equipments. "Topics are specific search areas that Google is developing with the help of expert contributors. Contributors to topics annotate websites that they think are especially useful, relevant, or authoritative to a topic with pre-defined category labels." But not only experts can contribute. You can select the topics that interest you and use Google Marker to annotate sites as you browse the web.
Google also has a list of general labels and those labels were used to categorize search results in the experimental view from last month. To annotate pages with the general labels, you can create a custom search engine and add labels from the list. I made a custom search engine to test the quality of the labels and I noticed that in many cases the labels didn't describe well the content of the page.
Many people enter very broad queries (like "Vista") and search engines try to guide them to the right results using refinements. One way to refine a query is by adding another word that eliminates the ambiguity (for example, "Vista reviews"), but this is not always the best idea because someone could review Windows Vista without including the word "review(s)" in the page. Having a list of pages that offer reviews could save the day.
Hakia, a semantic search engine that will officially launch this year, uses categories for general queries, like iPod or Italy, but they appear to be dynamically generated and look more like an encyclopedia entry.
It seems that Google Co-op's secret mission was to rebuild at a larger scale Google Directory (ODP), which also organized the web by topic into categories. One thing is for sure: this year, Google's interface will undergo radical transformations.
Related:
New ways to visualize search results
SearchMash