Put the blacklisted sites in a hash rather than a list, that way you can do a fast lookup. A bit cleaner would be to put them in a Set::Scalar, but this is a matter of taste. Since you need approximate matching, you could have a look at Tie::Hash::Approx.

If you'd like to get a list of URLs not in the blacklist, you could use a grep.

Hope this helps, -gjb-

Update: Oops, I should thoroughly read a post before replying, I didn't notice that a regex match was required. Thanks Abigail-II.