Windows 10, which by default will download updates automatically, appears to be hijacking customers' bandwidth to distribute those same updates to others.

The technology is known as Windows Update Delivery Optimization (WUDO), according to ComputerWorld, and it resembles BitTorrent in that Windows 10 devices can share apps and updates they have already downloaded with others. This could lead to faster downloads, especially when Microsoft's servers are under heavy load.

The technology is turned on by default, however, meaning that users will have to explicitly opt out of the service under Windows Update's Advanced Options panel. According to Microsoft's FAQ, WUDO will not download data if it detects that a computer is on a metered connection, i.e. if it has a monthly download limit.

WUDO will benefit computers sharing the same local connection too. If a house has a group of Windows 10 devices, one of which has already downloaded an update, WUDO will be able to grab the update from that device and hand it out to the other devices in the house. Microsoft says WUDO cannot access or change any personal files; it is only for distributing software updates.

BitTorrent, which uses similar ideas to WUDO, is a popular distribution system for large amounts of data that would be very expensive to distribute from a single server. By sharing the load with others, BitTorrent helps customers grab the files as fast as possible without putting extra pressure on distribution servers. This technology is also used by pirates to share copyrighted works without having to host the files somewhere.

With Microsoft looking to move Windows 10 to a service model, where the system is constantly updated, employing a similar model with WUDO may be good for distribution, but the fact that the service is on by default may come as an unwelcome surprise to some.