I commented on the first part of your question here in the thread, Ask Hubski users that hit puberty pre-internet: Do you remember finding your first "porn?". As for the second part of your question, I think that in some ways it really skewed my idea of what a baseline of sex between real people should be like, at least before I actually had sex.

When I was about 20-23 I was a bit disappointed that most of my partners weren't as confident in participating as what I was used to seeing in porn, but as I moved away from girls of that age range and into the mid to late 20's and beyond, I found a shift in the confidence and participation of my partners and certainly in their requesting and directing the flow of the sex.

That said, I still look at porn all the time. I know for many it's a cliche that guys are always thinking about sex and that many men don't operate like that at all, but for what it's worth I am one of those guys constantly thinking and fantasizing. Most of my girlfriends haven't liked that about me and I can understand where they're coming from. Generally this abates when I make it clear that I prefer the reality to the fantasy.