I haven't seen this mentioned yet: The description of the Open Source certification mark as published on the USPTO web site is quite intriguing:
"The certification mark, as used by authorized persons, certifies that the software license conforms to a set of guidelines published by software in the public interest."
I.e. Open Source is defined as conformance to guidelines published by SPI! That's quite nice, isn't it ?
The complete USPTO entry is athttp://trademarks.uspto.gov/cgi-bin/ifetch4?ENG+ALL+3+921980+0+1+141168+F+2+2+1+MS%2fOpen+AND+MS%2fSource