Free Wi-Fi is everywhere, but sometimes it isn't always easy to find. If you're at an establishment and don't know the Wi-Fi password, you might be able to find it in the comments on Foursquare.
Our own Alan Henry, an occasional Foursquare user, notes that this is actually very popular -- if you visit a coffee shop or other location with Wi-Fi, there's a good chance someone has listed the details on Foursquare. Just check the comments on that location. Even if you aren't a regular Foursquare user, this is a great reason to keep the app around. Always remember to take the necessary precautions to stay safe on those public Wi-Fi networks, okay?