Tokenism is the practice of including one or a few members of a minority in a group, without their having authority or power equal to that of the other group members. It functions to place a burden on an individual to represent all others like her. The suspicion of tokenism can undermine a woman in tech's authority or perceived right to hold her position.
In practice in geek communities this can take the form of inviting several men whose careers are well established to speak at a conference and, in order to appear gender-balanced, inviting one younger woman whose career is just beginning and who is deemed unlikely to assert herself, make demands, or complain. This type of power imbalance played out repeatedly contributes to community perceptions of tokenization.
Tokenization can also occur when one woman is asked to represent her gender in a field over and over. Rather than seeking out many qualified women, group or conference organizers tend to return to canonizing one or two women as the most famous or as especially expert.