I don't have IRL friends to discuss unix/tech related topics, so I use IRC for that purpose. Most channels I join are for tech related communities I try to contribute to:

#nixers.net, #bitreich, #2f30, #unix, #obsd4*, …

I then have 2 other channels joined in: #wmutils (which remains desperatly empty), and a channel I use as a personnal whatsapp bridge.

Sometimes I'll join specific channels like #crux or #vim-fr, but I seldom keep them open.