Exceptionalism is when a geek woman becomes extremely well known, not for their geeky work but for being a woman, or when a woman's arrival in a geek community is heralded with a great deal of excitement focused on her being a woman.
This issue is complex, as some degree of attention to women's issues and women participants in geek communities is merited. (This wiki is an example of such attention.) For example, women tend to respond better to women role models than to men, and so making women visible as role models is important. Discussion of women's issues in geek communities is also merited. However, excessive emphasis on and attention paid to the female-ness of an individual woman by the wider community can make her feel isolated, and, paradoxically, invisible in the sense of not being able to do any work, no matter how exceptional, that is more important to the community than existing there as a woman.
One of the most overt problematic forms of exceptionalism is when female participants are welcomed or highlighted due to their perceived attractiveness, or on the basis of their perceived availability as a possible sexual encounter to male participants. Some female participants also find that there is no achievement they can make that overshadows the mere "wonder" of being a woman, and some also find that no matter what her achievements she is attacked as "someone who is only respected just because she's a woman" or accused of receiving special favours due to being a woman.
- Philip Van Hoof made a very excited blog entry in 2007 titled And in case you didn’t know: Females are working on Tinymail!
- Stephen Hermann welcomed Sarah Hobbs to the Planet Ubuntu website with the message "I like to be the worst case of not being political correct, but I like to see more women posting to planet.ubuntu,com... To see the first time Sarah on this planet, I was proud to see this very "sexy lady" from Australia." wayback.archive.org/web/*/http://www.sourcecode.de/node/304
- Photos posted on Twitter with the mindset of "wow, how rare, a lady thing at a tech con!"
- Valerie Aurora, after Wikipedia editors described her as having an article only because of being a woman, created a fake homepage revealing herself to be a man.
- Matthew Garrett's response to Philip Van Hoof was "The day I stop crying myself to sleep over the free software community is likely to be fairly closely associated with the day when we think OMG-a-girling is even more embarrassing than the fact that there are so few women involved to begin with that someone might think they needed to point it out." 
- Randall Munroe's comic xkcd once featured a character authorising destruction (via EMP Cannon) of the computer equipment of an Internet user who made a fuss about a woman in an IRC channel: Pix Plz