From idea validation to the product - Buffer success story

The CEO of Buffer, Joel Gascoigne, wanted to create a social media scheduler but wasn’t sure what else to include. He decided to set up a signup form on his website and started conversations with people, asking what features they would like to see.
The MVP Joel created was a success, and Buffer went from an idea to a product people wanted to pay for in the space of seven weeks.

More samples can be found here:
https://blog.urlaunched.com/mvp-in-software-development-lean-startup/