Its a pain in the ass basically. it makes us genuine buyers go through hurdles just to activate the games, internet connection, activation codes, email addresses etc.
Far Cry 2 was a nightmare for me, it only lets you activate your serial 3 times before it cannot be installed again, I remember formatting my pc a few times to fix some other problem and forgot to revoke the license, when I finally got my pc sorted it wouldnt let me install the game because it though I used it 3 times already - its still unusable now.
I can see why some people might want to pirate games, less hassle, no cd cracks, no limited installs or anything. Thats a sad thing to say but its true, we need people to keep buying the games to support the developers, but when they make it difficult for us genuine buyers its a ******* pain!