On the other hand, the Research Triangle group is still pretty small. I think it's due to a different geography. Boston, London and NYC are huge cities with lots of people, including many scientists and bloggers. The areas outside of those cities - the 'countryside' - are really not that relevant to the sizes of those hubs - add a few people here or there.
On the other hand, North Carolina is a large state, in area and population, but there is no humongous city in it - all the scientists and bloggers are spread all over the state. Why would people from Asheville, or Charlotte, Greensboro, Winston-Salem or Wilmington join the Triangle hub when they don't live there? I think we should expand the Triangle list to include the entire state and rename the group 'North Carolina' people. After all, no state has more bloggers on scienceblogs.com than NC, not even close, yet no NC city can come close to one of the Big Cities elsewhere.
In the meantime, if you are in NC, no matter where in it, please join the Triangle location and increase our numbers, so we can compete for a Hub in the future.