Today Eclipse (Galileo) completely froze during startup. A message I've seen on one of the views was "Initializing Crucible editor annotation support" - I don't use crucible, but seem to have gotten this plugin with the Atlassian connector for the Mylyn integration.
As it's been possible to start with an empty workspace, I've tried updating everything - without success. When I discovered that the Atlassian Connectors bring their own Usage Data reporting (that I was unaware of), I've deactivated it. The effect of this: My main workspace works again, no freezing.
Plus I got a notification that the Atlassian Usage Reporting feature uploads some data and how to configure it. I don't hope that it will reactivate itself every now and then... Hope it will help somebody else as well as my future self to have this information available should this appear more often.
The problem seems to be workspace dependent (e.g. reproduction is difficult without that particular big workspace) I don't see how to report this issue in an actionable fashion. The eclipse logfiles didn't help debugging this either.