all of the above, just depends on who you are as a person. if your kind-hearted, u'll try and buy it and give up if u cant. otherwise, you will try to crack it and sell it if ur successful
I have jacked one IG in my life by jacking the AOL attached LOL. A lot of people use checkers. Some people find ones with hotmails attached and figure out the hotmail and put it on a checker list and claim it when it becomes available. I have a friend that brings a ton of usernames to the market by scamming the original owners.