sincerity isn't a contractual thing
Back-scratching dealios have been going on since humans started trading seeds and running for tribal council. Sometimes it’s good clean mutuality, other times it’s muddy.
Consider this: if a journalist said, “I’ll write glowing things about you, and you promote my newspaper,” you might consider that… questionable.
What about this? “I’ll interview you for my website, in exchange for which, you will agree to: send out a dedicated email to your entire list, tweet three times, Facebook three times, and give my people a discount on your XYZ… Deal?”
Clean or muddy?
Admiration isn’t something that can be brokered. Sincerity isn’t a contractual thing. You can’t obligate people to ‘like’ you. (Well you could, kinda. It’s called paid endorsements and politics.)
Admiration. Sincerity. True love. These are the rewards of putting great stuff into the world for the sake of putting great stuff into the world. Hopes for reciprocity? They’re healthy to have. Putting them into an agreement letter? Muddy.