In reply to Scott Edwards.

There were several dozen most of which are either small, tiny, or in the graveyard. Here's a pretty comprehensive list of some of the efforts: https://docs.google.com/spreadsheets/d/1f86L7vgHUW9wSLNNSunhjmtxtg6KlCOVpHGKbqUzW-Y/edit#gid=0

I love the Hypothes.is UI and they give me my data which is a plus. If you can't potentially own the data, it's a losing proposition (literally).