I've lost work several times this evening while using Confluence.
The first few times, when I hit the save button, the page reverted to the pre-edit state, and I was told there was a previously edited and unsaved version. Selecting the option to continue editing that allowed me to recover some of the work. This problem has occurred a few times before this evening. Nobody else is editing the wiki, so it's not a case of edit conflicts.
The last time, when I hit save, I got a prompt to login again. Once I did that, I saw that all my changes had been dropped! I'm starting to think I need to use OpenOffice to do my editing work and then import pages into Confluence, because I'm spending about half my time retyping changes that were lost.