Good question. We talk about it on the Irc channel all the time. I got into it a couple years ago thanks to an adventurous g/f and at this point I'd be bored stiff trying to have a vanilla relationship.

In our case, she actually initiated it with a simple comment one night. "Too bad you don't have a headboard on this bed" (as in, to tie me too). The next day I had big I-bolts drilled into the wall and it's been a whips 'n chains party ever since. I love it.

It's not everyone's cup of tea, but there are a lot more of us around than I thought. I think most people are either interested or not...kind of black and white. I'd throw the hint out there and wait to see the reaction.