would be cool to see who is on site right now and who was on site in last 24 hours.

also would be awesome to get irc channel/server. I think channel would be enough for such small site

Yep, online users is great. And a IRC channel actually builds up the community

#panda.cd on irc.p2p-network.net

Maybe an opt-out to go along with it?

Indeed, privacy options are also planned.