No, not in the comments sections of commercial sites, which may demonstrate more (New York Times) or less (msnbc.com) civility and literacy, depending on the news topics.
Nor in the dying, spam-ridden embers of Usenet or Google Groups--remember Usenet?--or the outraged postings of abused purchasers at consumer sites.
Nor, alas, does it necessarily exist in the emails sent by students, which are sometimes correctly addressed to Dr. Lastname but sometimes to "Hey Mrs. Lastname" or sometimes (and most irritating of all) with no attempt at addressing me, just an abrupt launch into a request that I respond as soon as possible. These I leave until last when responding, needless to say.
But politeness does still exist--in professional email.
A few years ago, I started noticing that a number of academics didn't just launch into requests or whatever when writing emails. Instead, the emails began with the sentence "I hope you are well" or another courteous phrase unheard of back in the olden days.
And the complimentary closes of the emails became more polite, too. Although a lot of people still apparently prefer "best," I've seen comments at the Chronicle saying that this is too curt, and in the last couple of years, I've seen a lot more variety in this part of the email, too: "best regards," "warm regards," "all best," "with best wishes," "cordially," and so on.
Of course, this doesn't always guarantee that the person types a name below the close. As often as not, the person closes the email without typing his or her name, letting the signature file (which has grown from the customary 4 lines back in the day to a 6 or 7-line mini-cv listing titles and posts) do the work.
I'm charmed by this politeness. It makes me feel as though I'm in a Jane Austen novel and am receiving a letter, not an email.
Now my question: have you noticed this, too?