I have to agree that Microsoft could put a stop to it if they really wanted to. As a musician, who's music gets ripped, I make it a point not to support torrents in any way, shape, or form.
On the Microsoft TechNet forums, they discourage using "leaked" versions, quote.....
"There are always many internal builds being used by the developers during the beta process, there could be several every week. These are used by the developers to immediately test bug fixes and new code. Some of these interim builds are shared with outside organizations, usually major third party software or hardware developers, for their own internal testing. These builds have not undergone the usual, extensive internal testing before being released to these organizations.
Unfortunately, it is not uncommon for one of these builds to be occasionally 'leaked' to the public and placed on Torrent sites.
Anyone who downloads and uses any of these builds is at risk, since they could contain malicious code that was added to the program before being placed on the Torrent site. This is very common. Whoever the person was who leaked one of these builds is of dubious character, since this violates every contract and agreement designed to keep these interim builds private.
Hope this helps".
Thank You for testing Windows 7 Beta
Ronnie Vernon MVP