What it laying?

Laying is basically like being a bookmaker.  With the introduction of betting exchanges, you can now offer odds on horse to win, and hence profit when they lose.

What's so good about it?

The attraction of laying is that it offers the punter much more flexibility.  Sometimes its hard to find the winner of a race but it can be easy sometimes to find one that wont win.  Similarly while we're all used to betting on "value" when a horse is over-priced, you can also lay on "bad value" when a horse is under-priced.

Example Lay bet

To be able to lay a bet you need to have fund to payout if it wins, so for example if you wanted to lay a horse at 10-1 and you had £200 in your account, you would be able to take bets up to a total stake of £20.

Of course if you are laying an odds on 1/2 shot you could take £400 of bets at 1/2 with the same £200.  If the horse wins, you lose your £200, but if it loses then you win £400.