Not having copy protection was a huge deal for me. When I found out the IC/SD opted out of pirate protection, it almost made me want to go out and buy
two copies of the game.
This is all entirely anecdotal, but I have weekly LAN parties with my friends each weekend. Even though the complete lack of copy protection would make it extremely easy for them to just install off of my discs and never purchase the game, every single one of them has gone out and bought the game themselves. Even when I told them the developer was cool with 2 people per key, their response was "I don't care, this game is awesome!". These are not wealthy people who have lots of disposable income to throw around, yet they didn't hesitate for a second on dropping $45 on Sins, even though they already had the game.
Contrast that to games with stringent copy protection mechanisms. It's getting so over the top these days, half the time *I* can't play the bloody game, and I own a legit copy! Add in over-the-top CDkey checking for local area network play, and it becomes impossible for me to demo my purchased games to my friends, to see if they'd want to buy it.
Lately in the PC industry, I feel more like I'm punished for being a legit customer by wading through piles of copy protection garbage just to get the game started. I also can't stand swapping CD/DVDs, so the first thing I do upon patching my new game is to go download a NO-CD crack - sometimes I need to get the NO-CD crack just so I can play my legally purchased game!
Anyway, enough ranting on my part

Point being is that most games with obnoxious copy protection measures, my friends have never bought. Contrast this with Sins, with no copy protection, my DVD readily available for my friends to copy off of, and 100% of them all bought copies of their own.
I gotta give a huge shoutout to Ironclad and Stardock on this. Hopefully the rest of the PC game industry wakes up.