Not really sure myself. Yes I would agree that there must be quite a few active runners in Ann Arbor with all the races Running Fit does, then some by Tortoise and Hare, plus I would think the campus would have quite a few runners (during the school year anyway). Guess you could advertise with flyers at some of the local races.... Dexter to Ann Arbor coming up. (I am running it.) Something simple but may get some people. Post flyers in the running shops around town might work. Seems most of the groups here are relatively small, a few have fairly large following, but I think they are the exceptions.

Run a contest for new members? Random draw of names from everyone joining in a two month period? Might have a running book I could donate as prize. (If I can figure out how to remove the "Property of Ann Arbor Library" from it.) Prize for "most posts", or maybe "new posters"

Too late! The contest was not announced and you have posted now, making you an "old poster".....

Your prize is to find more people from the AA area ;-)