I think it's due to people buying accounts etc.
I rerolled on a server that some RL friends are on and they have offered to let me have one of their other toons, but I like leveling (for the play-style experience) and making a name of my own.
On that note, I can't wait for patch 2.3.
15% less XP between levels from 1 to 60.
Also, more XP from quests.