This is an exploit, but more of a warning to twinks
Currently lightwell is bugged(?), and when killed, even in battlegrounds, gives xp amounting to an average mob of the caster's level.
As for exploiting this, i'm not too sure the uses as it is a 3 min cd, but with these new twink threads and all their popularity i think its fair i warn you about leveling with lightwell.
http://img21.imageshack.us/img21/6614/lightwellxp.png
Edit: i suppose if you hate twinks you could just keep setting down lightwells and hope they level off it?