: Google is good (not as good as WebFerret, but still neat).
And guess what; it runs on Linux.
It's actually a good deal more advanced than WebFerret; Google is the first search engine that actually looks for the number of Web sites linking to a searched-for site; thus, a site which is linked to by a lot of people will rate higher than one which no-one links to. This is good; because it means that a site which people think worthy of linking to (like, say, McSpotlight) will get linked to a lot; which will in turn push it up the rankings. Which means that a useful site generally ranks higher than a useless one.