'New' Search Enginge: DuckDuckGo.COM
I say 'New' because I doubt that it is that new but I only stumbled across it today. It could be useful for some as it seems to have an inbuilt filter which tries to eliminate unsafe search results.
I just tried several searches I knew would give 'unsatisfactory' results, even behind our firewall provided by our ISP, and it returned:
'No safe search results'
I think it might be a bit limiting for the more advanced user though: You don't know what results are not being shown and what the criteria for not showing them are.
Link: Search Engine Duck Duck Go
I'm the founder of Duck Duck Go
Hi, I'm the founder of Duck Duck Go. Thanks for checking us out! I'm happy to answer any questions you or anyone else may have. But more than that, I'm interested in making the search engine better suited for educators like yourself. For more info about us, check out our About page, which also links to an FAQ and other stuff.
You've hit on one thing we've tried to do to appeal to educators, which is a very good safe search. In addition to removing "unsafe" results, it also removes a lot more parked/spam pages that you'll find in the other search engines.
In answer to your question about limitations, it really shouldn't be that limiting. We have our own index and crawler, but also use Yahoo & Bing APIs to fill in the gaps of the pages that may not be in our index. And then we run those through our safe filter in real time so that you end up with the safe results from all angles.
Another primary feature that I think will appeal to you is our Zero-click Info boxes. For many searches, we provide definitions, explanations and related topic summaries on the page, i.e. with zero-clicks. This is good for students doing research and generally exploring topics/learning.
Anyway, I'd love to have an open dialog about what I can do to improve from your perspective. So don't hold back--I'm all ears!