I was at a board game convention, as a venue to launch my site gamerustlers.com, and although we got great reactions, what I really cared about was how many people walked up to the kiosk and actually signed up. The second metric was how many signed up on their phones. While in Beta the site is free so I can't call them "sales", but there is a HUGE difference between someone saying "Hey, great idea" and that person actually signing up, even when it's free to do so.
And I believe there is also a huge difference between someone signing up for your product and someone actively using it after signing up. In my experience, I found that many people will sign up for a product out of general interest, but won't do much beyond that stage.
