It`s a nice start and though I am not your target audience (a 37-year old male), let me make a few comments / suggestions:
1) The home page has way too much text in the middle - People don`t read that much text especially not when they have not yet been engaged (or given a reason) to. You need to do more visual marketing and make it easier to understand at first glance what the site is about.
2) I didn`t even notice the top bar navigation at first. It is way too subtle and I think a lot of people will not notice that nav area at the top.
3) You should make the entire block of text clickable on the left side navigation and not just the initial action words.
4) I went to diet and saw that the middle part of the page in IE7 over expanded it`s boundaries and made the left side navigation too narrow.
5) and finally, and perhaps most importantly, I didn`t see anywhere for your users to communicate with each other. These kinds of sites will work best when you give your users the ability to create a community and interact with one another. You can send use your own one, send them off to facebook, use forums, or use something like Ning for a completely free and custom social network but if you to really make something happen, allow them to come together.
Hope you find that helpful.
JC Cameron, President
VendorCity, Inc. - Your source for highly recommended Vendors
JC`s View: My take on technology and entrepreneurship