Minimum Viable Product

Just saw one of the youTube videos of Marty Cagan on Product Management. This time his topic was on Minimum Viable Product. Based on his opinion it is smallest possible product that really meets 3 criteria:

1. VALUABLE - Users will choose to buy/use it...
   
2. USABLE - Assuming they want to use it, they should figure out HOW to use it...
   
3. FEASIBLE - If it meets above 2 criteria we/company should build and use it when it is needed...

Generally the evidence of Minimum Viable Product is collected using prototypes (user prototypes & live data prototypes) and user testing (face to face or split testing).