This article takes note of affordances for counterpublic communication on social networking sites (SNSs). Because of the important ways that counterpublic communication is tied to specific platforms, it is necessary to understand why certain platforms are especially conducive (or are seen to be conducive) to counterpublic address. This article uses the example of the asexual community’s use of the SNS Tumblr to explore the affordances of the Tumblr platform for counterpublic communication, comparing Tumblr to the bulletin boards on the popular Asexuality Visibility Education Network website. This article modifies and extends boyd’s analysis of SNSs as networked publics to account for the technological affordances for networked counterpublics. It ends by briefly considering ways that networked counterpublics can be antagonized.