Gaydar = gay radar
Okay, I might get into serious trouble with this, but I've been asked dozens of times how you can tell a gay man or woman from his/her straight counterparts. ('Straight' means 'heterosexual' in modern gay parlance)
Some are obvious (I mean, do you need my help to know Richard Simmons and k.d. lang are gay?). But most are a bit more subtle, and it isn't usually a matter of how much product they use in their hair, or how much they follow professional sports, that really matter.
Some have said it's a sense that's difficult to describe, and I guess it is. However, I've distilled the following clues from my *years* (ahem!) of experience:
(Take it for all it's worth--I'm just having fun here)
#1) The walk
Gay men take short strides. It's true. Gay men walk like geishas wearing wooden sandals. Straight men, on the other hand, look like they're trying to compete in the long jump, extra slowly--very long strides.
Lesbians walk like straight men. A definite swagger. There's a reason there's a saying in the lesbian community: "If it talks like a dyke and it walks like a dyke, then it probably is a dyke."
#2) Awareness of people around them
Gay men need to look at every other person in sight. When in public, gay men are continually distracted by other people. It's almost comical (being so utterly predictable) when you walk in a restaurant or a shop, and all the gay men will whip their heads around to look at you. It's in our DNA, completely instinctive. Meanwhile...
Lesbians couldn't care less. Butch lesbians, in particular, are too concerned with their gadgets--they, like straight men, adore PDAs, CBs, BBs, and every other mechanical acronym out there. If it weren't for lesbians, the Radio Shack and hardware stores in the Castro and West Village would go out of business. (Restoration Hardware, on the other hand, is a favorite among gay men)
Gay men dislike nicknames. Gay men want their name as long and formal sounding as possible, like they really want to reclaim the name their mothers called them when they were angry. It's much rarer to meet a gay Chris than a Christopher, for instance. It's never "Tom", it's "Thomas". And forget calling a gay man "Andy"--it's "Andrew", or, even better yet, "Andrew Michael".
Conversely, lesbians will shorten their names to the most masculine sounding nickname possible. "Christine" is always "Chris", "Leslie" is "Les", and "Georgia" always ends up as "George" (no, I'm not kidding). If the name is impossible to shorten to a masculine-sounding nickname, like Jennifer or Virginia, then it's just a single letter: "J" and "V".
#4) Clothing fit
Gay men will wear it as tight as possible. For some odd reason, gay men are as obsessed with their pant size as straight women are with their clothing size. The difference between a 32 and a 34 presents as big a self-esteem issue for gay men (and, apparently, Jerry Seinfeld) as a 6 and an 8 does for a straight woman. It's not unusual to see a gay man stuffing his flabby frame into a too-tight size 32 jeans just so he can brag about wearing that size.
Lesbians, like straight men, like baggy and loose. Really butch lesbians will wear shirts as loose as possible in order to give the semblance of breastlessness (especially among those trying to look like 14-year-old skateboarders). Most of the butch lesbian women I know exclusively shop at the men's department, and that includes underwear (they prefer boxers).
#5) Music preferences
Gay men: bubble-gum Europop. Or House. Or Techno. No substitutions or exchanges. Gay men love Kylie Minogue, Robbie Williams, and Groove Armada. Unless you're a gay man or a European, you've probably never heard of them.
Lesbians love Country. Or Heavy Metal. Or Folk Rock. No substitutions or exchanges. Lesbians love anyone who has played at the Michigan Womyn's Music Festival. No one else even wants to go to Michigan.
#6) Smiling too much or not at all in pictures
Gay men grin from ear to ear in pictures. In an attempt to show as many of their pearly whites on celluloid (or memory sticks), gay men instinctively smile as widely as possible when their picture is being taken.
Lesbians, on the other hand, usually snarl. Maybe a pout. Maybe a threatening glare. But never a smile. Never. (Except the femmes)
Test your gaydar
Gay or Eurotrash? - There was also "Lesbian or German Lady?" from the same site but the link is now dead :-( I got all of these right (but keep in mind, they're not confirmed; I just agreed with the judges)
OKCupid's Gaydar Quiz - 10 male and 10 female questions, and I have to say some are a little tricky. I got 75% correct.
ABC's 20/20 Gaydar Quiz: Yeah, it's mainstream now. I got 8/10 right, but in all fairness, the picture is *small*.