Thanks for the feedback. I would very much like it to be a "tool" as you describe. I've gone through many design iterations, and have tried to keep the "clutter" down to a minimum.
I would be interested to know what specific design elements you think are contributing to this problem. I know you said it isn't really a design problem, but there has to be more to say about it :) Colors? The results on the right?
The huge font size is reminiscent of text intended for small children, which combined with the colorful logo makes the site look childish in my eyes. It's furthermore bigger than most text on the web, which makes it paradoxically harder to read for me. Flashy stuff tends to catch the attention of young people, but it tends to be tiring past a certain age (I'm 29). It also reduces information density, but this may be intentional.
That said, the results are very good, the classification by topic well done, and the small descriptions are a good alternative to the usual SERP extracts. I had troubles with queries typed in French (It turned mostly results in English), but I assume you're focusing on the English language at the moment.
Besides, the layout is clean and unobtrusive. I agree with axod and aroxwell regarding caching (one "batch" of results ahead should be enough)and pagination, and with ambulatorybird regarding the length and lack of fluidity of the name. At least one these characteristics should be dropped.
I think the font size is the most obtrusive to begin with - it's just insanely huge. I'm a Web 2.0 fan as much as the next guy and think most websites use a font size that is to small but... ouch.
I think that would be a good place to start - once you do that you may find that the mouseovers are distracting or jump around way to much now that your line-heights are smaller. Jury seems to be out on those, personally I'm not a fan but enough people said they do like them that it's a questionable change.
I think limiting the use of mouseovers could be valuable. By making off-site links (the actual SERPs) not have a mouseover while making in-site links (narrowing of categories, the more... link to activate BOSS, etc) could offer a subconcious identifier to your users as to what the next action will actually do.
For me, the highlight-and-underline-on-hover effect is very distracting. It would be nice if the search entry field had a stronger visual separation from the search results. There also needs to be a stronger visual separation between each search result. This might just be that I'm so heavily conditioned by Google, but I'm thrown off by the results being so far from the left edge of the screen. Also, the red, it's a little harsh, and the font size, it's a little big.
Otherwise, though, just playing around, this seems like a really nice search engine, the results seem great. If I didn't think it had a lot of promise, I wouldn't have posted a critique.
Regarding the "highlight-and-underline-on-hover effect", I liked that. It is really nice that the whole text area works as a link, clicking on a hit is easier. And the highlight, well, highlights that.
I would be interested to know what specific design elements you think are contributing to this problem. I know you said it isn't really a design problem, but there has to be more to say about it :) Colors? The results on the right?