Is WWOOFing Worth It?

I'm taking a one-year trip around the world starting in June, and I'm trying to find ways to offset my travel costs. I already know about sites like CouchSurfing and GlobalFreeloaders, but what about WWOOF.org? If you have done this before, how long do you have to work each day? What was your experience like? Does the work vary, or are you pretty much out in the fields all the time?

Any info. you can give me would be greatly appreciated!

Lindsey