If you are a big fan of the Slack messaging app for teams, you might want to check out Hamster Pad and their chat communities tool. The site helps users discover Slack communities and connect with each other, essentially creating a social network on top of the Slack API. The aggregate platform was created by Matt Schlicht and Adam McKenna.
Schlicht draws comparisons from the "Slack ecosystem" to 2007 era Facebook: "Slack, with 2 million daily active users, is not quite as large as Facebook was in 2007, but the opportunities are similar." Hamster Pad lets you add a chat, join a chat and see what chat communities your friends are in. The platform brings chat rooms to one place and provides basic data (the number of people online and total membership).