You can't count on a blessing from above. Those are venues for pitching to investors, not pitching to users. You gotta go ground up with forums, blogs, twitter, email.
Create quotas for yourself of the minimum number of people you talk to on each per day about your site. Signup for lots of forums, start posting in said forums. Seriously don't underestimate forums, they are still big because they are the ideal many-to-many venue of communication surrounding one topic. These are communities that are clearly labeled. You know instantly what kind of users are on there and how to cater your marketing to them. Although forums tend to be around more physical goods and concerns, if your application domain is productivity or something more abstract start hitting up bloggers non-stop.