i'm really wondering about conversion rates of the 'normal folks' as well. I'd think they'd be more skeptical if they just saw a random picture with a paragraph of text saying 'we'll let you know when we launch, give us your email address'.
Where we see the opportunity now (and what we're building) is how you interact with that person after they show their trust and allow you to contact them. it's very important to win them over in a way that is authentic.