As Kirk points out (and Blogger acknowledged), some users of Google's Blogger who publish via FTP have been seeing a new post that says "eeyore is cute!" (awww, yeah, see the pic above) - and some non-FTP users who chose to get post confirmation emails may also have got an email about a test "eeyore is cute!" post.
His guess as to what happened was correct: "An internal load testing at Blogger somehow got some wires crossed that let their test post get published on some blogs."
Here's a screenshots of one of the affected blogs:
So not to worry, if you got that post or email your blog hasn't been hacked, it was just an internal mixup at Google, all you have to do is republish your blog and that'll fix it. Clearly there are Pooh fans at Google!
Would be even funnier if this started happening on 1 April!
Note: low resolution Eeyore pic downloaded from Wikipedia, made even smaller and displayed on the same basis i.e. believed to be fair use; but if the owner disagrees please let me know.