I'm not saying it's right, but it does feel scummy. If you think about it, it feels way less scummy to just ask for money. Asking for a tweet is like saying, here you can have this free thing if you degrade your friends' experience on twitter by a tiny amount first.

Do it a bunch and it adds up.

Whereas me paying someone one dollar doesn't degrade all of my friends' twitter streams.

I know I don't want to read people's "free stuff" tweets. I'd rather they didn't show up in my feed. I only want to read recommendations when they are genuine. Not when they were required.