Interesting thread and comments.......I'll focus on two comments, by Naeblis and Prisca.
Both made points that I think are very true. I won't restate what they said because each one said it better than I can, but I do agree that social reprecussions (which seem to be more dire for men than for women who express some bi thoughts or feelings) do play a role, as does the notion that it would seem to me, in most cases, to be mush easier to express oneself as having bi curiosity in an online discussion than in actual face-to-face discussion, at least for some people.
Actually, I was going to begin my reply by saying that refiner's fire had "courage" in not only bringing up this subject, but especially by touching on what men might feel with regard to bi curiosity. Then I thought, no, that sounds stereotypical....then I saw Naeblis' comment, and yes, perhaps indeed there is that 'stigma' attached to it when a guy expresses himself on such a matter, thus maybe he is showing courage by mentioning it. Does that mean it takes no courage on a woman's part to express bi curiosity? Not at all, but it does appear to somehow be different for men in some respects, as if there is more of a stigma attached to it.
As far as whether it is "natural" for a woman to express or act upon such feelings, well, the word "natural" can be a loaded word, easily used by some (especially the religious right and jws) to condemn such feelings or expressions.
Interesting thread refiners. Xena, helpful posts too.