They are not expected to contribute towards funding maintainance and upgrades of the lab infrastructure and have no financial obligations towards the lab. The pop pool provides pop and chocolate bars to its members. Items stored in the fridge without approval of the Hegemon will be removed immediately. By posting to the first one you reach all members of the lab. The second of these contains all student members of the lab, and the third one all faculty members.
All lists are un-moderated, but subscription is by approval only.
The procedure for joining these is analogous to the one described above. Follow the standard netiquette and keep in mind that talking to people directly can often be more effective than posting to an e-mail list.