We had a shoutbox on some reincarnations of the SFSE forum (some time between 2013 and 2015, I don't remember exactly). When the shoutbox was first introduced, people were excited and used it quite a lot. Slowly but surely it became unpopular, maybe one message per week. On the other hand, SFSE has more players now than it had back then. So, from my perspective, it's worth trying.