Good article - describes it well.
I've been signed up as a host for a couple of years now and yes it's working fine. However, we don't get many guests - a Spanish couple cycling from Edinburgh back home and an Australian guy who did a tour of England is all we had so far. Both were very nice, had a shower, cooked their food, went for a bit of sightseeing and slept in their tents. Next day I rode with them for a bit to show them the scenic bits and best routes.
Good experience for my kids as well to let them take part in their adventure a bit.
Had one slightly dodgy sounding enquiry once and turned it down. Was probably just a lack of English misunderstanding, but I didn't want to risk it. Was no problem at all as they don't get your exact address until you agree.
I thought we'd get more, being right next to a NCN and not far from Cambridge, but I guess I'd avoid the Fens as well if I was on a tour - it's not the obvious touristy route...