This is more a content issue but to really build the community is have more fully fledged profiles - with location, bio - make it one or two lines max and a website or blog link. If we are what we think/read then it would be a great starting point in finding cofounders or people who are on the same wavelength. I would also agree on seeing the latest comments - and maybe highlighting posts which you've commented on/ or submitted showing if there were new comments that you haven't read. So show "7 comments | 3 new" so it would be easy to come back to your home page and see how the discussion has evolved.