Remember that empirical test I did about whether a post deleted in Blogger would be deleted in Google Reader? I decided to take it to the logical conclusion, and see how far back Google Reader went. After all, at some point things have to drop off, right?
By dint of scrolling for half an hour, I got to the bottom of the posts contained in Google Reader: they went back to the beginning of 2008. Four years and two months of posts, 564 in all. At least three of them were significant posts that I deleted from my blog.
So yes, you can get rid of embarrassing posts. It only takes four years.