Windows 10’s new WiFi Sense shares your WiFi password with Facebook, Outlook, and Skype contacts.
Though they won't actually see your password, if they're in range of your network, they can use your bandwidth without entering the password. They won't be able to get onto your LAN but who wants somebody using our bandwidth?
There will be options to disable WiFI Sense when you install Win 10 or on the settings page, but... [^o)]