New Blogger has had troubles this morning, which you may have seen with slow requests and 502 error pages.
We are working on this and hope to get it resolved very soon.
Update, 1PM: These issues have been resolved. We are continuing to monitor and diagnose closely. We apologize for this morning’s poor performance.
You may still see 502 errors on occasion, but waiting a few seconds and reloading the page should work. This is mostly limited to a handful of blogs, however.