Humblebrag: Twitter-only phenomenon?

Have you seen humblebrag?  Urban Dictionary defines humblebrag as following:

Humblebrag: When you, usually consciously, try to get away with bragging about yourself by couching it in a phony show of humility.

It's like someone is pretending to be humble on the surface, but in reality bragging about how remarkable her life is.  Let me show you some examples of humblebrag:

For a girl who doesn't like wearing makeup, this LA paparazzi thing is a bit intense.
— Bethenny Frankel (@Bethenny) May 26, 2012

This is how the pros do it: receive copies of new book, accidentally pour curried soup down back offridge interior while on phone to BBC.
— Nick Harkaway (@Harkaway) April 16, 2012

Further to @elonmusk's complaint, I *have* to answer the phone when Caller ID is blocked, because it's often the White House. Sucks/rocks.
— Waldo Jaquith (@waldojaquith) May 24, 2012

What is funny about them is that I don't see humblebrags in other social networks, like Facebook, Google+, LinkedIn, etc.  Although the definition does not limit itself as tweet, but I only see them on Twitter.  How could that be?

Humblebrag hall of fame;
follow @humblebrag to learn from masters

It's because people are shaped by place and place shapes them.  If you are at work, you behave a certain way.  You understand what's acceptable at work, and be shaped by your work environment.  If you are a bar hanging out with friends, there is a different understanding of what's acceptable.  People's behavior is contextual.

Because Twitter allows more relaxed unstructured posting, it encourages users to behave more freely.  Another reason is pseudonymity.  Twitter permits multiple twitter handles to represent different persona that people might have.  Combine this with everyone is talking to everyone else publicly as if they are in big giant party hall, it is not surprising that you see self-promoting humblebrag on Twitter the most.

If you want to master the art of humblebrag, I suggest you follow twitter handle dedicated to curate humblebrag tweets: @humblebrag.  Or you can learn from watching Jenna on 30 Rock, backdoor bragging master: