Roz, Thank you so much! I'll message you to get the ball rolling on the PR.
As to finding members, right now you can use the search function on the main page. But, as of now, I've made the location field optional because some people are very private. I am working on a Google map that shows all the members, but the crazy thing is that we have TOO MANY members for just one map, so I'll have to break the map down by timezones or something similar.... I hope this helped. The best is to start or join the group in your area and then post a note in the forum there. I've found that more people respond to someone than post the original "hello".
With regard to the "groups" - some are actually active groups (with meeting times and all that), but most are just a place to find others in the area.
PR: Great. I just sent you a message. (top left corner). Yes that testimonial is great. right, this site actually "does something."
since niche socials are all the rage right now, I think that angle could work. Tennis is interesting because it is like the perfect reason to have a social network site - you hang online, but also have a reason to get together in "the real world."
There are a couple of cities that come to mind where the group growth has been very very fast (austin, portland, DC, westside LA)
Mark, looks like your're getting some members with PR experience interested in helping. I have very little PR experience, but I tell a good story. I'll leave it to the experienced ones. All I know is that you Site is totally awesome. Red beans and ricely,