I guess there are mainly two reasons why people ask questions like that:
1) It's funny/amusing/sex is awesome to talk about because it's still a bit "naughty" and we can all hide behind our screens and indulge our curiosities
2) The actual nature of "real" sex is still very much a hidden part of society and talking about it is generally frowned upon (by people such as yourself), and therefore people are dying to know whether what THEY do/like is normal or acceptable.