Earliest Testable Product
The first functional version of the app still has various protruding corners and unpolished edges, but achieves the desired effect. You can test this version by the very curious users. That Feedback shows where the greatest potential is.
Earliest Usable Product
This version is so well developed that early adopters would like to use it. She doesn't win one yet Beauty pageant, but the added value is obvious.
Earliest Lovable Product
Your users love it. They tell their friends about it and are willing to pay for it. You have a marketable product ready to go live.