Relationships aren't so easily defined that we can simply say, "everyone can potentially have a relationship with everyone," or "biologically we are driven to have relationships only with people we feel compatible for reproductive purposes."
To illustrate this point, I will relay two conversations I've had in the past four years. I had my astrological/psychic chart worked out by a friend who was into that sort of thing. He worked out my astrological details then asked my sexual orientation, asking me to be brutally honest. Okay, brutal honesty requires the answer of "I'm straight, but open to the possibility that I just haven't met the right guy." My friend then rolls his eyes and says, "every guy says that." Then he pauses, looks back down at my chart and says, "Oh, you're a Pisces. You're probably serious."
The second conversation is with another friend with whom I enjoy a very close relationship. He's solidly homosexual and we tease each other all the time. However, we openly acknowledges that while he enjoys the open spirit and amusement factor of the teasing, he realizes I'm so solidly straight that there's no chance I would actually follow through on my teasing.
Believe it or not, there is a point to this. The point is that net relationships are generally a reflection of the relationships we wish we could have in realspace. It's possible to explore concepts in virtualspace you wouldn't dare touch in realspace, which includes alternative lifestyles such as bisexuality and the like. But this assumes you're curious to begin with. I've had a lot of people hit on me over the Net in the past ten years (being a MUD admin virtually guarantees I get all sorts of attention), and after a while I learned how to distinguish between the legitimately female players and the guys who hoped to get special treatment from me by pretending to be female. If I really didn't care about gender (and was unscrupulous as the guys trying to scam me) I would have accepted the attentions from the female pretenders and pursued a relationship, sexual or otherwise. But I didn't because the thought of entering in a romantic and/or sexual relationship with another man doesn't appeal to me. In other words, I still haven't found the right guy.
I've had very few guys hit on me because they were genuinely interested in me. But regardless of the motivation, I haven't accepted any invitations, simply because that's the way I'm wired. I've met some very good friends whom I love dearly in spite of gender but that love translates more to the Greek agape, which is to say brotherly (non-sexual) love. Depth of emotion is gender-irrelevant to me, but I won't pursue a relationship based on agape.
Anyone who attempts to convince me they're something they aren't (either female or intelligent or whatever) won't get much beyond a pat on the head from me and some encouragement to go have fun. I'm not going to buy into insincerity on the Net regardless of intent.
"Humor. It is a difficult concept. It is not logical." -Saavik, ST: Wrath of Khan