"Do things that don't scale" comes to mind.
<a href="http://paulgraham.com/ds.html" rel="nofollow">http://paulgraham.com/ds.html</a><p>You eventually want a product that users come to on their own, but in the beginning, you could talk to users on both sides to get them to come to the table. If you are interested in the space, this should come easy!<p>For instance, talk to people who want apps and sites created. Formulate their requirements into really great, attractive, clear posts on the job board. Give them logins to your site so that they can see the post. Now you have real users, and real job listings.<p>Now "advertise" the job listings, and/or your site in general with freelancers (tweeting the jobs, tweeting at freelancers, announcements with popular hashtags, telling your freelancer friends about the new site, etc etc). As others have said, when there are job listings, the freelancers will stick after their first click when they see there are listings.<p>Get feedback from both sides. I think the freelancers will be more able/willing to communicate electronically their feedback, and you will already be in touch with some people who had apps/site projects, so you can get feedback from some of them directly. Rinse and repeat many times.<p>I do think the existing freelancer sites need improvement in the personal touch area, so I think it's totally possible for you to compete, and even a major advantage to you in the beginning stages since I think success will hinge upon you doing things like this, which don't scale.<p>Good luck, please post a follow up to let us know how it goes!