The beta version of Windows 7 has been widely distributed through torrents and other file sharing systems. But now some commentators claim Microsoft deliberately allowed the package to get into the hands of pirates.

A beta edition is one which is effectively finished: in theory the only changes which would be made before the official release are to solve serious bugs which are found during the beta testing.

The beta of Windows 7, the successor to Vista, isn't officially out until later this month (the details will likely be announced at the Consumer Electronics Show which starts on January 7, 2009), but copies of the system have been available to illegally download since late December. At the time of writing, one torrent site (Mininova) had 12,000 people downloading or sharing one copy of the software.

In theory this is bad news for Microsoft: it would represent mass piracy and lost revenue. However, it's led to some great publicity as those who've downloaded the system seem pleasantly surprised with how well it works, particularly on machines which struggled with Vista. It's also questionable how much money Microsoft has actually lost given that many of these downloaders would have been unlikely to buy a legal copy of Windows.

While many analysts have been suspicious, Joe Wilcox of the Microsoft Watch website has outright accused Microsoft of leaking the beta itself.

"The timing is perfect, from a marketing perspective. The leaked build hit BitTorrent sometime on Saturday, right after Christmas when the Windows geeks had nothing better to do and bloggers and journalists had nothing better to write about." (Source: microsoft-watch.com)

Both Wilcox and other writers have noted Microsoft doesn't appear particularly concerned about the leak, though the firm does appear to suggest it came from an outside tester rather than the company itself. (Source: dailytech.com)

The copy which is available has a built-in 30 day time limit and, unlike previous editions of Windows 7, 'enthusiasts' don't seem to have found a way around this yet. While this is pretty normal practice for test editions, it would make it possible for Microsoft to leak the software without it affecting the final product.