Although at times contentious, the current recruitment promotion has certainly sped up leveling. The triple experience point bonus comes to mind first, but the ability to give levels at a rate of one per two gained is also a real boon. The rule is that the levels can be applied to a character lower than the givers current level, capped at level 60. Theoretically someone who has reached level 60 could donate enough levels to raise another character from 30-59* in a matter of minutes.
This new mechanic is pretty easy to use and potentially abuse. Málfurion of Wildhammer is not happy with the change. To quote "I just saw a Warlock go from level 31-59 in 10 seconds in front of my eyes... The new recruit a friend is bull > <.... NERF NERF NERF!" The post was met with some disbelief, but it clearly is a possibility. Some players indicated that they have something similar in mind. Abilene of Aegwynn believes that this practice ruins the game for some.
The rules don't say that the recruit must be a new player, or even someone other than you. I know several people who have rolled secondary accounts, just for this speedy leveling. I'm torn between if this counts as abuse or clever use of mechanics. So far, I haven't seen anyone banned for abuse. Blizzard hasn't said how long this promotion will last.
I see some very short records for leveling in the future. Theoretically someone with two recruited characters could level a brand new character from 1 to 59 in minutes. So they'd only have played time for 11 levels.
What do you think the new record will be?
* The rules state that recruits lose their bonus levels at 60, so the bonus to the receiver is capped at 58.