User blog comment:Krufix/Dota2 - Is it REALLY so much harder than LoL?/@comment-2248060-20130121005152/@comment-213.181.192.163-20130121050537

"There's a couple more things you need to know about Dota than you do about LoL, such as how to use the Courier and Denying, but again, it's not too much to learn."

It was mentioned along with couriers.