I paid for Pinboard long ago—its vibe did strike something with me. (Back then I was using online bookmark managers, did not have the habit of paying for software, times were different). I stopped using it shortly after I paid for it though. I needed to save a lot of reading I had open in tabs once, and bookmarklet stopped functioning—I went to the main site and the UI was behaving erratically as well, so I figured APIs must be down or something.

The reason I left was not so much the outage itself but the fact that I paid for the service, while the free ones were right there available for me (Delicious anyone?). I felt a bit silly paying for the vibe and not something more primary.

EDIT: This was years ago, hopefully it’s more reliable now though I haven’t been following them too closely.