A quick list off the top of my head:On Facebook there is the "Maemo fan group". There are also an assortment of more general, Nokia-related groups. On Twitter there are #m.occ, #maemo, #N810, #N800, etc. On Jaiku there are #itT, #maemo, #n800. #jablet and #ldug are also tangentially related. On Flickr there is "What is your Nokia tablet doing today?" On LinkedIn there is the "maemo.org Group". On last.fm there is "Maemo users". On IRC, there is #maemo on Freenode.