Searches today on the Pirate Bay BitTorrent site, for example, returned multiple listings of Windows 7 Build 7000, which Microsoft identifies as a beta candidate in the filename. The torrent is a disk image of the 32-bit version of Windows 7 Ultimate; a 64-bit version is not yet available.

The most heavily trafficked Windows 7 BitTorrent on Pirate Bay showed more than 4,300 "seeders" -- the term for a computer that has a complete copy of the torrent file -- and about 7,500 "leechers," or computers that have downloaded only part of the complete torrent. Less popular BitTorrents of the file on Pirate Bay claimed an additional 1,000 seeders and more than 3,000 leechers.

On Saturday, a day after the first copies of Build 7000 , Pirate Bay's prime listing showed less than half as many seeders as it did today.

Similar increases could be seen on other BitTorrent sites. For example, Mininova listed almost 20 Windows 7 BitTorrents -- some of them duplicates of the ones that appeared in searches of Pirate Bay. Two of the torrents on the Mininova site had more than 4,500 seeders each.

Bloggers who have downloaded the pirated operating system -- such as 's -- are reporting that its end-user licensing agreement labels the new build as the beta that Microsoft has promised it will in early 2009.