Thanks Sacha. For idea validation, I'm always curious where people draw the line. You set up a sign-up form on an existing page, yes. But how many signups do you need before you consider it validated and worth pursuing? 10 signups? 100? 1000?
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.