1) Half Rainbow:
Half a rainbow; the colours red or pink, purple and blue, representing bisexuality, or a person being bisexual.
As a rainbow is the symbol of gay pride, a person being gay and homosexuality, half rainbows symbolise the half-gayness. Is gayness even a word? I don't know, but I do know that the half rainbow (also bi-pride flag, I think) looks better when red or pink is at the top, if it's going top to bottom, rather than left to right. The purple is always in the middle.
I believe that the red or pink represents female, and the blue represents male, the purple therefore representing the crossover.
The name of an up and coming artist on deviantART. I say up and coming... They aren't partically famous or popular, but they do have nearly one favourite for every picture, which I guess is kind of good. They are so named because of the meaning of Half Rainbow being the the bi-pride version of the gay pride rainbow.
3) Miss Half Rainbow:
Representative of bisexuality and bi-pride on MySpace, such as Gay God and therealgaygod are for gay pride. There aren't many representatives of this section of LGBT (Lesbian Gay Bi Transgendered/Transexual) for some reason, apart from iDo, which is a group rather than a person. She likes to call her MySpace page her BiSpace.
4) HalfRainbow / Miss Half Rainbow
Me, if you hadn't guessed. I'm bisexual, and I'd like to point out that it's no different to any other sexual preference, except that I have twice the chance of being turned down, I guess! No, I don't fancy everyone, does a straight girl/guy fancy every member of the opposite sex? Right. Anyway, I'm proud of my sexuality because, well, why shouldn't I be?
Most of Miss Half Rainbow's banners have a half rainbow background, but as I speak (January 3rd 2008) HalfRainbow has yet to post a picture with any sort of half rainbow.