As I said, you need to ask your members what else you can do to benefit them. Start getting them involved and that you care about their needs. You can create a discussion topic and send out an email to all those members, asking them to join in.
If you're not going this route, then you should ask yourself what's the point of this site for those members and why should they spend their valuable time on it in the first place? This is about:
value = benefits/cost
also, why should they spent any time there as opposed to LinkedIn, Facebook, Twitter? Which is about:
what you have developed is very generic and sounds basically just another LinkedIn. So, you need to develop your competitive advantage - if you can't think of this yourself, then by all means ask those that are already member of your site.
P.S. why did you link to my profile?