The ODP doesn't work on that kind of reciprocal payment either. It works like this. You give something away. Then ... you give SOMETHING ELSE away. And while you're waiting for people to get around to using what you gave them, you ... start working on something else to give away.
Sometimes people aren't as quick as you'd like them to be. I'm not complaining today: someone else just went to a lot of work at Project Gutenberg to ... give me more work, building another book to ... give away. I've been waiting for months for someone to do that, and I had no clue it was about to happen. Of course, in the meantime I had other things to do.
That's the way distributed projects work. You never know when someone will build on your work; you never know when someone will give you something you didn't know enough to want. The trick is to give away enough that somewhere, someone is ALWAYS using or building on what you gave.