Definition:
Offer a pretotype version of your product or service on a very limited time basis to see if there is any interest before making any long-term commitments.
Example:
Sacrificing their own apartment for one night, Airbnb founders created a simple website in which they offered an alternative to hotel rooms: an air mattress + simple breakfast for $80/night (a bargain in San Francisco). Much to their surprise, 3 people signed up very quickly and they collected $240 on their first night. Airbnb is now valued at over $10B!
Resources:
Exponentially Platform: helps you work out which ideas you should invest in, by tracking your experiments and using data to tell you what will work.