Barbara Feldman: Quote as a Noun

The last comment is the most accurate. It should be 'quotation.' The mistake has been made for so long that it's accepted. But it's similar to using 'ain't' in place of 'isn't' or 'doesn't' in the sense that we see 'ain't' as grammatically wrong but it's so common it's now in the dictionary. 'Quote' was used as a verb for 300 years before someone "nouned" it.

Yes, it's accepted. Technically, it's wrong.

The 'back clipping' or apocopation of the word 'quotation' rendering it abbreviated, may be an acceptable short-cut for those who have little regard for the history, richness and heritage of a specific language, but such lackadaisical attitudes leaves the language faltering and unsure of its future.
Granted, there will always be changes to the vocabulary as terms are introduced, and meanings modifies to suit the occasion.
But a noun is a noun and a verb is a verb.

Simply because something is done, as a shortcut and out of sheer laziness, it doesn't make it right.
The English language is arguably the richest and most widely spoken language (whether as a first or second language) in the world.
Like any other respected, hallowed and traditional instituition, it has rules.

be so good as to kindly abide by them.

They are NOT wrong. (Or should I say informally, "thems people aint be wrong"?) People have been using the word "aint" since the 1700s as an informal version of "are not"; that doesn't make IT ok to use. No amount of time or usage will make it so.

When a usage note or article or whatever says that it's ok to use "quote" as a noun in informal writing, they're not saying that it's a good idea. They're saying that it's ok for you to ignore the rules and sound like an idiot in informal writing because no one is going to hold you accountable for doing so. Obviously, they are wrong.