We are often asked why Bi.org tends to use the shorter, less formal word "bi" rather than “bisexual". The practice is not an accident, but rather the result of careful consideration. Bisexuality, like homosexuality, heterosexuality, and asexuality  is a scientific term that describes sexual orientation. While these terms are important in sex research and medicine, in everyday language they can often sound clinical and inappropriate. Indeed, anti-LGBT extremists use words like "homosexuals" in an attempt to dehumanize and stigmatize gay people.
Over the past century, as our society has come to understand that not everyone is "wired" to be heterosexual, our cultural concept of sexuality has evolved from something people do to part of their identity and sense of self. That awareness has given us terms like gay, lesbian, and queer. While it's still common for individuals and organizations to refer to groups of bi people as "bisexuals", we think the time has come to move on from this practice. We have therefore chosen to use the colloquial term "bi" whenever more casual, everyday language is appropriate. We generally use “bisexual” as the precise term for the sexual orientation and “bi” as a sexual identity.