Noun. The name for learning some nugget of information about a person or event specifically from Facebook. It's a portmanteau derived from the name of Facebook's founder, Mark Zuckerberg, and the expression "a little birdie told me."
A little Zuckerbirdie told me that it's your birthday!
A little Zuckerbirdie told me that you got engaged!
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.