I think the cool thing about this, especially as an older person (40's), is that it creates a low-stress, high-interactivity scenario. So while some of the people may just be acquaintances that come to one or two potlucks, some will inevitably click and become more than just once a month dinner guests.

Forming friendships after schooling isn't hard, but it takes work. That said, I've had a good number of small social interactions that usually don't even lead to an acquaintance over the last decade, and even those feel good just to get out of my shell. Then there's the people I'd recognize if I saw them again and maybe remember their names. And a small but close group of about 12 and counting have become incredibly close friends that have recently begun mingling with my prior set of really close friends (different states, so we have a couple yearly gatherings).

But that interactivity is pretty hollow. I'm sure it cures the itch but it's not the same as having a friend.