There seems to be quite a lot of literature on designing a good landing page MVP for validation purposes, but little on how to properly follow up with leads and interested users beyond sign-up so as to maximise product validation and user retention.
So, say you got a user interested enough to sign up for whatever it is you're offering which is, however, not yet deliverable as a product. How do you continue to engage with them beyond that point?
Many thanks for your help
This is where growth-hacker types come in. Your MVP did capture contact details right? Email/Call tweet users, and find out what/they did like didn't like etc.
Just talk to customers.