Here is the entire Wikipedia article on this phrase:

"Dictated But Not Read" is a phrase used at the end of a text to warn that the written material has not been personally written or verified by the author. The material may have been dictated to a secretary when the author had no time to proofread or edit it.

This practice is more common within the medical community, though its appropriateness is still debated.[citation needed]

References
BMJ (British Medical Journal)

If we turn back the clock to 1 March 2007 (oh man, check out the maelstrom in that daynode), we can see the page as originally created. The creating user, whose only contribution to Wikipedia was this single new page on that date, did so with the comment: "I have started this asrticle as a stub. It's my first try at editing, sorry." I was taught never to apologize right off the bat. That forgiven, you can see how similar yet watered down the current page is compared to the E1-ish glory of the original, despite the latter's lack of an exact definition of the phrase. Comparing the two, you can feel the slime in the nooks of the current version, rubbing off on your hands as you turn it over and examine it.

"Dictated but not read" is a phrase commonly used to sign off on correspondence where formality takes a backseat to speedy communications, or where such correspondence is routine. When this is not the case, it is a discourtesy to the recipient of the letter.1

This practice is used often within the medical community, though it's appropriateness is still under debate.2

References:
1How to Win Friends and Influence People, by Dale Carnegie
2BMJ (British Medical Journal)

Don't get me wrong, I love Wikipedia, but in this case it failed.

Okay but who cares? This is the internet.

None of us, I presume, have secretaries to whom we dictate our nodes. So what good is DBNR to us? It isn't. But we have LBNR/LBNW: Linked But Not Read/Watched. LNBR is the more heinous of the two, and is used when an article is linked which was chosen for its title alone, but the linker has not read it. (If you just skimmed it, you could say LBNRE or LBNRT or LBNRC or ETC.) LBNW is a much more acceptable usage, and is employed with a YouTube (aut alia) video to indicate it was chosen based on its title (likely for the musical content) but that the user linking it has not watched the video. But don't take my word for it, because I just made up these abbreviations.

Love and peace,
raincomplex

(dictated but not read)