I commented last week on the notion that Barack Obama was mean—or at least insufficiently courteous—to his immediate predecessor in his inaugural address. (Reagan speechwriter Peter Robinson, for example, dings Obama for this, among other perceived failings with the speech.)
But as the New Yorker's Hendrik Hertzberg points out (and as a quick look at previous inaugurals bears out), obligatory expressions of thanks to one's predecessor are a relatively new, post-Watergate phenomenon.
BTW: On Facebook? You can keep up with Thomas Jefferson Street blog postings through Facebook's Networked Blogs.