I found the following on howtogeek.com:
This feature lets you share Wi-Fi network access with your Facebook, Outlook.com, and Skype contacts. It works in the background, automatically sharing networks you choose to share and downloading credentials for Wi-Fi networks your contacts have shared with you.
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I found the following information on pcpatriotsmobileit.com:
You can turn off Wi-Fi sense by changing your Wi-Fi Settings.
1. Click the Windows menu icon and type Wi-Fi Settings.
2. Click on Change Wi-Fi Settings.
3. Click on Manage Wi-Fi Settings.
4. Under the section for "Connect to networks shared by my contacts" uncheck the boxes for Facebook, Outlook.com, and Skype.
5. Click on the ON/OFF switch (if it is on) for "Connect to networks shared by my contacts" and ensure that it indicates that it is OFF.
After doing this, I recommend changing your Wi-Fi password, because if your PC was up and running, your password has already been saved in the server database, even though supposedly it will no longer be shared.
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Another option:
You may also change the name of your Wi-Fi network to avoid your password being saved. Just add "_optout" to the end of your Wi-Fi name, such as MyHomeWiFi_optout.
Also, consider what would happen if all of your contacts had access to your wi-fi network and downloaded copyrighted content.
I once had a problem with someone who had accessed my wi-fi network years ago. They downloaded a movie. The producing company noticed the download, traced the IP address, contacted my Internet service provider, and demanded that my ISP provide them with my personal contact information so that they could continue with legal proceedings. My ISP refused to provide the information, but they contacted me and informed me that I needed to secure my Wi-Fi. They also told me that the next time that this occurs they will provide the requested information to the requesting company. They informed me that there could be a fine of $20,000 and/or 5 years in prison for a single offense. My Wi-Fi was somewhat protected against this on multiple levels until Wi-Fi Sense accessed my password. I have now changed my Wi-Fi password after deactivating the Wi-Fi Sense.
If I had left it on, it would only take one so-called friend to access my network, download a song or movie, and with my luck the producer would notice it and try to take me to court. With your Internet connection, YOU are responsible for what your Internet connection is used for. YOU are responsible for ensuring that it is secure. Now Microsoft is destroying that security with Wi-Fi Sense.