[sgdesign]

It depends on how many people land on that page. If you have 100 visitors a day and you have 10 sign-ups a day, that's an awesome conversion rate and probably a sign you can consider your idea validated.

Or you can approach it the other way around. If you have 1000 emails and you expect to convert 5% of them for a $20 product, you know you'll earn $1000 from your current audience, and can plan from there whether or not that's enough to justify working on a project.

Those are all random numbers obviously, but you get the idea.