Basically you host someone to stay at your place and provide them with meals/accommodation in exchange for a few hours work a day. It could be anything - cleaning, gardening, farm work, help learning another language, childcare etc.
I think it would be a great idea, just a bit wary about having strangers stay. We live on a 4000 acre property fairly rurally so not sure if many people would actually want to come out here.
Anyone done this sort of thing before? How did it work out?