Purely anecdotal, but maybe you can find the sources or someone can correct:
From what I know, the guys behind Meteor started out as a YC-backed travel application. The feature of the app was that it’s real-time. When they demoed it, people were impressed by its real-time nature (and keep in mind, this is like 5 years ago).
The app ultimately failed, but people were interested in the technology, and thus, Skybreak (?) was born. Then, after the team gave a talk somewhere, I believe it was YC demo day, someone walked up to them and said they have this domain called Meteor.com, and offered it to them.
Meteor started off as a closed source product, where the license implied something like “you’ll owe us a bit of your revenue, as we agree.” Naturally, the open source community pushed for an MIT license, and then the its been version after version of updates, then 1.0 happened.
For what happened since 1.0 and now, Geoff recently gave a talk at MDG that’s worth finding. I think all of his talks are a good watch.