Make a room for "general posting" and collect all the gifs and watercooler talk there. Gives everyone a space where they can go to decompress, doesn't change your normal business use.

Im also of the opinion that having a dedicated space for more "real time" communications can be really helpful as well. Team branded support room, for example. Having a space that everyone at least casually keeps an eye on can really save everyone a lot of time (especially when operating remotely) if a team member comes across an issue.