http://cocoasamurai.blogspot.com/2006/09/tip-pragma-mark-organizing-your-source.html explains it better than I can, but this is one of the little things that I've stumbled across in sample code.

Basically, by using

#pragma mark -
(which will give you a blank line)
and

#pragma mark whatever

it means that your editor will contain a list under @ implementation MyClass listing all your methods. It's a way to organise code and make it easier to jump to methods. I can see a strong case for getting into the habit straight from the start.