To illustrate the links between internet and real-world community, I usually point to MeetUp or UpMyStreet conversations. Now I can add LiftShare.com, a UK-based site for organizing car pools. Because this involves letting someone else into yoru car, or vice-versa, they do profiles for driver/ride matching based on characteristics that might affect your willingness to give someone a lift (e.g. gender, smoking/non-smoking), as well as offering both public and private groups, thus extending the old Echo/WELL pattern of invitation-only conferences back into the real world. The other interesting pattern is seeing what public groups have formed (reg. required to list those groups.) Most are fairly pragmatic -- "For all residents and businesses in Barnet" -- while a few mix pragmatic and social components -- liftshares among backpackers, Arsenal fans riding to games. The growing assumption of ubiquitous access, and the subsequent overlap of online and offline groups to the point where all groups will have some online component, is fascinating to watch.