In the past several days, we've seen some performance problems with Blogger. In general, the app has been slower and users have encountered an increased number of Internal Server Errors.
We are aggressively fixing the source of the errors and have pushed several fixes in the past few days to address the problem. There is additional work to do to return Blogger back to a more responsive state - and we're on it. If you find yourself seeing errors, please logout of Blogger and completely shutdown your browser. When you restart your browser and log back in, you will be on a new appserver which may be less loaded and thus performing better.
Thanks for hanging in there as we straighten out this issue.