One symbol which continues to remain popular is the lower case Greek letter lambda. The symbol was originally chosen by the Gay Activists Alliance of New York in 1970. The GAA was a group which broke away from the larger Gay Liberation Front at the end of 1969, only six months after it's foundation in response to the Stonewall Riots. While the GLF wanted to work side by side with the black and women's liberation movements to gain unity and acceptance, the GAA wanted to focus their efforts more concisely on only Gay and Lesbian issues.
Because of its official adoption by the GAA, which sponsored public events for the gay community, the lambda soon became a quick way for the members of the gay community to identify each other. The reasoning was that the lambda would easily be mistaken for a college fraternity symbol and ignored by the majority of the population. Eventually though, the GAA headquarters was torched by an arsonist, destroying not only the building but all of the organization's records, and the movement never recovered from the loss. The symbol, however, lived on.