It certainly seems more convenient than writing down or spelling out your WiFi password to friends but there are some obvious security concerns.
Microsoft claims that this feature improves security and reduces frustration. Now, instead of painstakingly spelling or writing down passwords for guests or friends, they can automatically acquire them as soon as they come in-range of your home network. The company’s FAQ states:
“When you share Wi-Fi network access with Facebook friends, Outlook.com contacts, or Skype contacts, they’ll be connected to the password-protected Wi-Fi networks that you choose to share and get Internet access when they’re in range of the networks (if they use Wi-Fi Sense). Likewise, you’ll be connected to Wi-Fi networks that they share for Internet access too. Remember, you don’t get to see Wi-Fi network passwords, and you both get Internet access only. They won’t have access to other computers, devices, or files stored on your home network, and you won’t have access to these things on their network.”