houdel Loc: Chase, Michigan USA

Win10 includes a new feature, "Windows Update Delivery Optimization", which could be good for you or could be bad for you depending on your particular situation. What it does is instead of downloading an entire update to every user, it downloads pieces of the update among several users, and then each user collects the pieces of the update it didn't get from Microsoft by uploading the missing pieces from other users. The idea is to speed the delivery of updates by not having every individual user downloading the entire update from the Microsoft servers. The downside is you will be uploading your portion of the distributed update to a number of other users, which could use up a good portion of your bandwidth.

The linked article explains this topic more fully and describes how you can turn off this feature if that would be to your advantage. Note also that if you have your own private network running multiple Win10 computers, you can restrict the distributed update file sharing to within your network only, which will save you some bandwidth.

http://www.komando.com/happening-now/319080/windows-10-secretly-uses-your-bandwidth-to-distribute-updates-to-other-people