Can someone explain to me what "back" and "lay" mean in sports betting?

[CFH]

Betfair.com is a site where you can act as the bookie aswell as the punter.

So basically you can create odds yourself and allow other punters to back the odds you have offered.

So laying means you are basically backing something to loose, meaning your offering them odds you have highlighted in pink for other punters to back.

Backing is in blue and is when you are the punter and backing something to win.

I hope thats clear

Fuck me, I'm more confused than ever... I think I understand what you're saying though, I guess I need to find another site then. I've never bet on sports in my life, but I just wanted to check the odds on whether Wlad - Haye will go the distance (I'm 100% sure it won't) and what the over/under odds are...

Edit: Hold on a sec, does that mean that I can get 1.1 odds that the fight doesn't go the distance by backing someone elses bet??