The closest I have ever gotten to something like that is when someone sent me a dvd off my amazon wish list for my netflix recommendation framework which was pretty cool.
A list of all the developers whose free software contributions are necessary for a website to be used would not be short. It would be absolutely ginormous.
Maybe if it wasn't free, nobody would be using Rails and Mongrel - everybody would be on C# and Mono. There is always competition, so "should be rewarded" is really determined by the market. You can't just work on anything and then demand money for it.
Mongrel that costs money would be a different product from Mongrel that is free.
Yet they can afford to hire employees who know how to deploy Mongrel and Rails. Programmers and sys-admins aren't cheap, neither are executives, marketers, salespeople, etc. Even if you're running a tiny Web startup, you should be able to afford small donations.
edit: You can treat the donation as a "license fee" if that makes the accounting easier to deal with
A license structured as "acknowledge your use or you will be sued," with penalties specified, as opposed to "please acknowledge your use" might have a different effect. I really have no idea.
Kent Beck's post from last month came to mind.
By mentioning Mongrel you increase the visibility and reputation of Mongrel, which increases his visibility and reputation. Now, when he introduces himself to someone he can say, "I wrote mongrel." And they will say, "cool!" instead of "what's that and why should I care?"
I only found out Mongrel was written by Zed Shaw when I read his now infamous rant about Rails and its community. (I'm not that a big Rails guy, but I did use it for a project).
Says something, no?
I remember he used to rant about something like not getting a job, but he can't have been serious? Maybe he is asking 1000$/hour, or his ego really makes him unemployable (which I doubt). But even back in the "big rant day" I think there was a footnote somewhere where he said he basically was fine and didn't need a job.
Maybe without Mongrel, nobody would listen to his rants to begin with. (I guess he did lots of other awesome stuff, but I only know him for Mongrel).
I can't tell if I'm joking or not.
(To be clear, I think Zed is awesome, and he has the right to use whatever license he wants. Oh, and we use Mongrel).