Like many on here, I love anal. Though I'm not prepared to pay extra for it and I only enjoy it if it's clear that the woman enjoys it too. Which, for me, is true of any form of sexual activity. AnthG points out that many people think there is no discernible difference in the feeling you get from being in a cunt or a bum. I disagree; in my opinion there is a difference. My (civilian) occasional fuck buddy loves anal and adores it when I take her bareback from the rear, first up her cunt, then out and into her bum, a few strokes and back into her cunt. Porn movie territory, I know, but it's incredibly exciting both physically and because of the taboo element. And I know you're not supposed to do it for medical reasons, but she's the one who insists on it and she's suffered no ill effects despite the fact that we've been doing it, spasmodically, for several years. Anyway - going into both holes alternately, bareback, enables you to make a "feeling" comparison. The vagina is very slightly ridged or textured, which of course generates the friction which helps you to come. The anus is totally smooth - presumably to allow completely free passage to what normally comes down the tube. I'm not saying the difference is huge. But it is quite distinct. She always asks me which I enjoy best - cunt or bum. And I can never make up my mind. When I'm in one, I think yes, it's this one. Then when I switch, I think the same. The bum is tighter to begin with but after a few minutes of vigorous activity there's little to choose between the two holes in terms of tightness.
To go back to the OP, I think anal is far more practiced and "normal" than it was 15 or even 10 years ago. Certainly as others have suggested, porn has had a lot to do with this. But I think the real game changer has been the internet. This not only enables us to access truck loads of porn of all varieties for free, it also enables us to discover from forums like this that what we might have thought was a guilty, disgusting urge which we should suppress and feel ashamed of, is actually something that, while not everyone's cup of tea, is perfectly reasonable and normal and enjoyed by huge numbers of people. 15 years ago, if memory serves me right, there was still a lot of excited talk about blow jobs, with lots of people complaining that the wife or girlfriend flatly refused to oblige and that if you wanted a good blow job, unless you were lucky, you needed to pay for it. 15 years on, this seems incredibly quaint and even anal is now becoming widely available without the need to pay for it.
I wonder what sexual activity, now rare and hard to come by, will be pretty normal 15 years from now...