Twitter = retarded.
Given the textbook definition of punk outlined below, you could say twitter is punk. See 1:a - something or someone worthless or unimportant. Therefore, Twitter is punk.
But refer to point 3. According to the outlash of the general punk rock scene, Twitter is definitely not punk because this ludicrous fad is a documentary on conforming to the whims of media induced popularity.

My definition of Twitter: One more vacuous hole to throw your time into that you will in no way benefit from. A genuine waste of resources. The murder of time that could be spent in productive ways, or at least paying attention to the road you're driving on.
A sad, festering wound on the face of all humanity, when such mediocrity can grab the attention of the entire planet when things of great significance and discovery fade into the background as though they were never there.
Raise the standards of the internet, people. I swear this thing can still be useful.

punk  [puhngk]
–noun
1.Slang.
a.something or someone worthless or unimportant.
b.a young ruffian; hoodlum.
c.an inexperienced youth.
d.a young male partner of a homosexual.
e.an apprentice, esp. in the building trades.
f.Prison Slang. a boy.

2. punk rock.

3.a style or movement characterized by the adoption of aggressively unconventional and often bizarre or shocking clothing, hairstyles, makeup, etc., and the defiance of social norms of behavior, usually associated with punk rock musicians and fans.

4.a punker.

5.Archaic. a prostitute.

–adjective
6.Informal. poor in quality or condition.
7.of, pertaining to, or characteristic of punk rock: a punk band.
8.pertaining to, characteristic of, or adopting punk styles: punk youths; punk hairstyles in various colors.
Origin:

http://www.flickr.com/photos/doctabu/sets/72157620497679512/detail/
well then, you may like the content of the link above... my basic thoughts are that most youth/ adolescents are laughable in their own self importance...but eventually mature into something of value, or just go away. the twits are interesting in the way they are finding their footing and potential use... iran is an example of using the technology for its imediacy, kinda cool in my book.