Probably only the owners of the search engine. If you look at your web stats and the stats posted by others, you see that the big three control search and Google is the grandaddy.
It's an old search engine, but nobody uses it. On top of that, the results suck. It's good they have their own crawler, though.
I use scrub the web only for submitting my websites but its ihave some 40-50 visitors daily I think so