Their Wikipedia entry is hilarious. The short story seems to be that they used the Swedish copyright law (or rather the lack of one) to run a torrent indexing site (and apparently a very successful one.) Just for fun they sent rude replies to all the threats they received. They made the standard rule of the new Internet work for them: get the eyeballs, get the money. A Swedish newspaper reported they had an ad take of $75K a month!
The best part of the story is their attempt to buy Sealand.
As digital copyright law, and international law, struggle to catch up the world over, there won't there be many such opportunities and instances?