Note that "Web 2.0" is a term in common use--and not in any sense or manner the intellectual property of O'Reilly and Associates.
Google pushes Web 2.0 forward:
Google AJAX Search API Blog: AJAX Search in TypePad and Blogger: By Mark Lucovsky, Software Engineer - Friday, September 22, 2006
Many of you have already integrated the Google AJAX Search API into your blogs. Yesterday, I built some sample integrations on both TypePad and on Blogger. I went a little overboard, but I did this to demonstrate a few ideas that you might want to clone into your own blogs.... Both samples offer the following features:
Google Search Form in the sidebar with tabbed search results displayed in the center column. A mix of web search, blog search, and site restricted search happens in parallel. Clicking the clear button next to the search form removes the search results.
Video Search Solution hosted in the sidebar. You can search for new videos, or playback collections of videos coded into the template. Using this solution its trivial to expose your users to 100+ videos.
Map Search Control Solution hosted in the sidebar. Your template controls the center point of the map. Its very easy to augment the map with a collection of hotspots or favorite places. In addition to these pre-defined searches, the solution contains a regular search bar. Each search result offers a direct link to a details page as well as driving directions...