I'm developing a new web-based tool to help WhiteHat SEO folks write better content. Before doing a full-blown launch, I've decided to run a private beta so that I can get user feedback and work out all the kinks for going wide with it. Users sign up with their email addresses, and I've been collecting quite a few, but I'm not sure what to do with them. I know in the long haul, the list presents a good opportunity for marketing niche products to them (maybe Clickbank stuff, idk), but since they are just beta partners at the moment, what I don't want to do is drive them to blocking my emails because they feel they are spammy before I even launch my main product. What do you think? Should I worry about monetizing them yet? And how about after my launch. Should I try to market more inside the app, or just go ahead and take all new users and put them on a autoresponder list? Thanks in advance for any advice!