So you put me on a waiting list for an invitation to your new product. Fine. You have a few more kinks to iron out and bugs to squash before you let me and the rest of the world in.
DON'T ask me to tweet or otherwise promote your website in exchange for that invitation - that pisses me off.
I'm doing YOU a favor by trying out your product in the first place : the web is saturated with LaunchRock template signup pages, so it's already a miracle that I put in my email in yours.
Startups should let users experience their product before requiring ANY kind of signup / personal information - so if a splash page was enough to get me to put my email in that signup box, you're already getting a lot from me.
But telling me I now need to start promoting your product before I've even tried it to get access to it in the first place ? Ugh.