Blinkx beta had some problems.

Here's what I found as I tried the Blinkx beta personalized search. It
didn't work right. The local content indexing never finished, really
the program just hung there and wouldn't finish the task. At this
point I uninstalled it and then it gave me a message to ask if I
wanted to delete the indexing which I never saw any evidence of. I ran
it all night long and didn't get to the final result. I know this is
beta software and so I don't expect everything to work right. But if
the software takes a long time to index, wouldn't this throw some
people off who just want simple search? I think that's where a lot of
personalized search arguments miss the point. People want accurate
search results without all the hassles. If this kind of search is a
hassle like I had, then people will not be using it, maybe on the
obsessive-compulsives, which narrows the market for search greatly.

I did use their standard search for finding things on the web. It
worked fine and got results similar to Google or Yahoo, so that's not
really an improvement.

Once again, it's simplicity with relevant results that matters to
searchers. As far as knowing what you might search before you search,
the need for that might just be a bit overblown.