I actually have a counter rant concerning the term "creepy" but that's kinda offtopic. Instead I'll give the short version:
There's two reasons I can see being "creepy" to be bad, and that is being threatening, or being gross. Nothing else. Threatening is obviously rather impossible here as very few people give out personal information; the worst I could see is harassment and that requires things happening over a prolonged period. As for being gross... I can sympathize with that though note I'm very adamantly against sexual repression, for personal reasons. If the "gross" response is from simple distaste, and not a kneejerk reaction against stuff "that should be private," then I'll sympathize. It's perfectly acceptable to be grossed out by someone hitting on you.
So yeah. I reserve the right to hit on people, though I will of course stop if they ask me to (note that I generally only do that to people I already know pretty well). Innuendo and such is more grey area, but if you're grossed out just inform me and I'll stop. Further of note, I made an IRC chat for most that stuff to be funneled into anyway, rather than cluttering the boards. Finally, there are of course the forum rules, but I do hope you have further reason to hit the report button or confront someone than just submission to authority for submission to authority's sake.
I don't know what "social boundaries" have been crossed, but I DO know that they are cultural constructs that differ from person to person, place to place, culture to culture. We may very well have different boundaries here than you are used to. Courtesy of course still exists, so make your opinion known and set up your own boundaries, and you should be fine. If you're not fine and something happens, I'll be on your side.