I would argue a large part of the problem with essentially a "donate" button is that the flow is all wrong for a service provider, especially one that basically only has a one-time-setup cost for implementation. Consider a likely sequence for someone who goes through the whole process:<p><pre><code> * X visits your site, is mildly intrigued.
* X notices the donate button, passes it up because you have
provided no real motivation for them to do so
* X gets an API key and pokes at it lightly
* X integrates
* ... time passes ...
* X is appreciative of the time saved, and might give you money...
IF they saw the button right then.
ELSE more time passes without paying.
</code></pre>
I haven't seen filepicker.io's implementation (which has since been taken down, apparently), but did they include a 'donate' button in the API documentation? Did they email people after X time had passed, or Y API calls? The vast majority I've seen never take these steps, they just slap a 'donate' button on the site and wonder why it doesn't make them rich.<p>If they didn't repeatedly try to poke people, it's out of sight and out of mind. The hallmark of any good service, really. It's unfortunate, but not surprising, and I wish I knew a more reliable way to get money out of people who are appreciative.