It's on par with the services where people charge you for them to Tweet about something and they don't seem to to have been received to badly. Just another form of advertising I guess.

I have a separate account for that stuff - JonIsAWhore I believe it's called (it's been a while since I used it).

I don't mind these things. If I have friends who abuse them I unfollow them or hide their updates.

The only thing I'd like is to know that I can get the product / service the old fashioned way if I want by paying cash, and keeping my soul clean if that's what I choose to do.

Very good account name. Twitter is the pimp and the advertisers are the Johns. Google and FaceBook are pimps too.

I'm not on Twitter, but I'd immediately point out to my friends that I don't want them to spam me.

I don't know. People will be tempted to get whatever free shit they can through such a service, but I think that urge will be attenuated by their desire to not piss off their followers.

I could see myself using this to purchase things that I think my followers would like, or at least not hate.

Plus I've seen plenty of things like this on Twitter already: "RT this to be entered to win!". It doesn't anger me when I see those things from the cool people I follow.

This is how the music industry is adapting. There are facebook apps that behave similarly - you have to LIKE the band to unlock content and downloads.