As search engines go, Exalead is a bit stealthy at the moment, but will be launching in the UK later this summer. The company has been going since about 2000, if you believe this Wikipedia entry. I've been playing around with it, and notwithstanding the limitations (or otherwise) technology behind it, it has a number of features that are quite appealing.
(Actually, before we leave the subject of technology, read up on Quearo, an attempt to index multimedia content that Exalead is involved in).
Anyway, to get back to the main topic; there are two things that are quite interesting about Exalead. Firstly, results are displayed as thumbnails of the pages that are thrown up. This is pretty handy if you are a more visual person, as you can see the overall 'shape' of a page and recognise it quicker than the link text.
Secondly, it's possible to filter out results. Most search engines are very good at getting lots of results, and some of them are good at ordering results according to how relevant they think they are. However, Exalead looks up subcategories and allows you to remove them.
For example, say I want to book a sailing holiday, but I don't want to fly too far and I know pretty much what I want. I type in 'sailing holidays in europe' into Exalead, and the usual suspects are thrown up - lots and lots of results, of which a few look interesting.
Click on the button marked 'More choices' in the box called 'Refine search' on the right hand side of the page, however, and I can start eliminating results I don't want. It would be safe to say that a journalist can't afford a crewed charter, or a luxury charter, and a dinghy would be a little too small, so all of these can be removed. Remember the search engine has already identified these things as subcategories. It's possible for me to search by what I don't want - effectively, the search engine actively helps to narrow the search.
This is all a very complicated way of saying that Exalead has potential. Sure, it wants the user to do most of the work. This won't be convenient to many. But the really important searches - the ones where users are looking for a single, high value item of information - could well be where Exalead is a strong contender. I don't expect this technique to be limited to one search engine for long, of course.