The third place is the local bookstore, barbershop, pub or diner, the place where you feel comfortable hanging out, socializing and enjoying free time with friends -- in other words, your home away from home. Third places create a leveling space where people from various walks of life can come together and forge friendships. For teens and young adults who do not have the blessing of a safe home, third places also sometimes provide the refuge they desperately need in their lives.
Lots of spaces have the potential to be third places. For instance, back when Captain Midnight and I were newly married, our third place was "Barnes & Noble night," where a group of friends met once a week or so in the B&N cafe to chat, drink sodas and granitas, and generally act like complete goofballs. But third places don't have to be purely physical locations. The folks from Barnes & Noble night originally met and befriended each other on a local BBS, which functioned as a virtual third place. Captain Midnight's current third place of choice is his online gaming group. Through this group he's met and befriended people from all over the world, and they merrily inflict bad puns on each other and enjoy slaying each other in various games.
Third places are critical because they create and maintain a sense of community. Often, the difference between merely enduring in a place and thriving there is the sense of being part of a whole, which a good third place can provide. (This is one reason why I was so miserable living in Eugene, Oregon -- while it's not a bad town, I had no third place there, so I felt isolated and wretched much of the time.)
Despite their importance in creating community, third places can be fragile. There's a bit of alchemy to creating a third place. If one provides all the other elements -- neutral ground, accessible, low-profile, egalitarian, etc. -- and no regular patrons show up to establish habits, it ain't a third place, Jack. You can lead a horse to water, but you can't make it drink; in the end, only the patrons decide whether a venue receives third-place status. And even a well-established third place can go belly-up if the owner makes too many changes too fast and scares off the regulars; if a third-place business starts operating under new ownership which decides to change everything just for kicks, the established patrons will disperse. Good luck finding new patrons to replace the old ones. Worse, some established third places just shut down with little to no warning, giving the former patrons nowhere to go. WHICH SUCKS. And keeping a group of patrons together when their chosen venue has vanished (or been altered beyond recognition) is remarkably difficult to do.
So if you're fortunate enough to operate a third place venue, DO NOT MONKEY WITH IT. Seriously. It's easy to do more harm than good when you make changes, especially if you choose not to listen to your patrons and instead inflict upon them whatever idea comes into your pointy little noggin. Don't expect your regulars to put up with those shenanigans. And if you don't worry about losing your current patrons because you expect to draw in new patrons with your shiny stuff, please note that the kinds of people who are most drawn to the new and shiny are always looking for the newest and shiniest; they'll probably move on to another place in a month, leaving you flat. There's no need to work at being the place where the cool kids hang out; instead, you want to be the place where everyone wants to hang out, precisely because no one feels the pressure to be cool there.