I found a new, or new to me anyway, search engine today called
Factbites bills itself as a topic-based search engine. It appears to search wikis and open encyclopedia as well as providing other answers. According to Factbites’ marketing it offers users meaningful, relevant sentences from every site in the search results.
I found it useful for searching for biographies on major, high profile donors (in this case the person I am researching is a member of the Forbes 500)
Although many of the individuals who I research will never be prominent enough to appear on Factbites, or in the Wikipedia, this can be very useful for finding concise biographies on very prominent individuals. In addition, it gave me some sites that Google, alltheweb, and Yahoo hadn’t picked up.
The site is in beta, and I don’t know how extensive it is at this point, but it could become a very interesting resource.