Hey folks,

I've been browsing the net for a while and ran across www.torrentz.com
Essentially what they do is search a number of other reputable torrent sites and index the results on their site. Its pretty amazing that the site doesn't have any of its own content but is able to grab 1 million unique visitors on a daily basis. Does anyone know what tools/methods they would use to accomplish this?

Would they grab data from other sites databases or rss feeds? Is xml relevent at all to accomplishing this? I've also been looking into sphinx as a meta-searching tool.