Spoke too soon — Six Apart already has a gang sign. The blogging service's co-founder Mena Trott throws it with a decidedly ungangly grin:

This image was lost some time after publication, but you can still view it here.

6A property Live Journal has its own sign, flashed by Andrew Anker and 6A VP Anil Dash (who can't keep his still):

This image was lost some time after publication, but you can still view it here.

Meanwhile, Googler Brett Lider gives love to the Information Architects (a sign in use since '02):

This image was lost some time after publication, but you can still view it here.

Enough, people. Any more of this and an actual gang will come up to SF (there can't be real gangs in San Francisco, can there?) and pop some caps in our collective asses.

Photo 1: Friendly gang sign [Alaina B on Flickr]
Photo 2: LJ [Alaina B on Flickr]
Photo 3: More web gang signs [Every Breath Death-Defying]
Earlier: One more @%!*$ gang sign [Valleywag]
Earliest: Blog-wiki gang wars [Valleywag]