A brand new search engine just entered the fray. Wikia, the brain-child of Jimmy Wales (of Wikipedia fame) uses an open-source concept similar to the famed online encyclopedia. Rather than the opaque and somewhat suspect algorithms used by Google, et al (which can be 'enhanced' by a hefty outlay of corporate cash), Wikia relies on user feedback to generate reliable, authoritative hits.
Obviously, as they're on day one, the results aren't the best. I ran a trial search for an upcoming 7th grade project on desertification in Africa, and only found a few useful sites on the second or third page. On the plus side, it only generated 476 hits--far less daunting than the 770,ooo on Google!
However, as more people use it and supply feedback, the results should improve exponentially.
One nifty feature the site provides is a mini-article at the top of each search page, fully editable, allowing users to add information. Again, most of the searches I used didn't generate an article, as they hadn't been created yet. The site proclaims the primary purpose of the article will be to provide definitions, "disambiguations," photos and a 'see also' reference.
I doubt I'll be sending students to this any time soon, but it's definitely worth keeping an eye on!