Chicken and egg problem - as a viewer (not a bidder), why should I visit a site that is nothing more than a sponsored advertisement? And if nobody visits, why would anybody bother to bid for messages?

Despite all the negativity above, I just wanted to say.. I kinda get a feel for what you're trying to do and there's definitely a good idea lurking in here somewhere. I am reasonably convinced your present implementation is not /quite/ right, but as long as you're agile on your feet and respond to what feels the right thing to do, you might end up with a hit.

Turning these sorts of ideas into hits is a bit like landing a helicopter onto an invisible boat. There's no target, you're just flapping around in the breeze, but if you delicately push it the right way, you might end up with something (or nothing).

You might want to consider starting out with 10 messages per week (or 3 days, etc.). You're ultimately creating artificial scarcity. If you reduce the supply of messages further and thus increase the price, it's likely you'll see higher quality messages -- which in turn should drive traffic. You can "prime the pump" by starting with a longer message lifetime.

The disadvantage is that you may train users to visit weekly instead of daily, which is obviously counterproductive to driving traffic.

Why no ads? How would you keep them off?

Why would I want to see this site? There is absolutely no point to viewing it, and therefore why would I pay to put something on it?

Also, how could this possibly take more than 3 hours to make?