I learned about it from creack (lead contributor according to github) @ a startup meetup in SF.

Things that impressed me:

1. super passionate

2. he was very receptive and quick at squashing bugs I reported (real or not)

3. docker was super portable (the same across all linux distros)

4. they (the docker team) had real solutions for the long application deployment times that were plaguing me

Everyone seemed to know it would succeed, which is rare around here.