Caveats: These numbers are from one of today's large solution workshops, not from the larger group that I suppose will attend the keynotes or other sessions this week.
XX Footprint: 5.7%
This is pretty crappy (er, I mean low), even for tech conferences. I know there are chick developers out there. (Anecodotal example: I am managing an Omidyar-internal open source development project, and all of our groovy developers from Colorful Expressions are female...and at least one of them is here today, since she has started working on Ruby/Asterisk projects.) Maybe this ratio is reflective of the open source community, since the general software community is not overtly macho.