I saw a billboard like this in Westwood last weekend.
Reebok is doing the anti-Nike thing and has launched the "Run Easy" campaign. Their claim is that you don't have to run until you puke or be all that competitive... you should be running easy.
That makes sense. Why do they need all these billboards to say that? If I thought running was something for the elite, I would have copped out a long time ago. It's a highly personal thing that isn't really supposed to have that much pressure. It's walking... but faster.
I've always considered myself more of a Nike person anyway. Running? Just do it.