There are many social differences to regular coffee shops, but people who go there watch sports, play cards and argue with each other over politics, usually. We call these places "καφενεία" (kafenea). The expectation there is that most people know most other people, everyone knows the owner and the setting is usually not lavishly furnished (just a few tables and cheap chairs).
https://www.theguardian.com/business/2016/jun/08/mcdonalds-c...
http://www.nytimes.com/2014/01/29/arts/design/lessons-from-m...
1) In the case of coffeeshops, many people go there to work. The noise of people gabbing could drive them away. This is a pet-peeve of mine; the local Starbucks seems to double as a daycare, making it really difficult to focus.
2) How likely is it that the people gathered share enough common interests that they want to talk to each other? E.g. in my case I'd want to be able to strike up a conversation about politics or philosophy or music-making or tech. If no one already-gathered shares any of those interests then I'm not staying very long.
These aren't insurmountable and there's probably others that haven't occurred to me. Again, I like the idea.
1.) The coffeeshop isn't an office - people can talk. If it's too loud, that's on you (the person using it as an office) to find another place.
2.) You already have something in common - you want to talk!
I've seen this idea of the "talk table" work in retirement homes, not sure how well it would fare with a younger crowd.
2.) Right, I do want to talk, but the number of subjects I can converse about is a tiny fraction of those on offer. If I show up and the topic is rebuilding engines or flower arranging - two topics I know nothing about - I'll have nothing to contribute.
A slightly ironic statement from someone whose blog apparently covers "frankly anything". :)
I know that many places already have communal tables but I find that unless there's some explicit display a place is meant for a certain purpose, many people who want to chat / meet new people won't initiate because they can't be sure their neighbours are open to it. If they purposefully decide to sit at a 'talk table', then you can be sure they are.