My understanding was that “none” is from “not one”, so always singular. But it turns out that it’s also “not any”, so can be either way. Ignorance fought.
The American treatment of a collection as singular (especially as a company) is inconsistent and illogical.
“IBM is going to buy our product. They say they want …”
Note the inconsistency? The UK way is far better, treating the company as a collection of people.
“The use of commas within quotation marks,” said my English teacher, “may make it look like the quoted speaker is pausing in a in midsentence, but that is nevertheless the convention”.
I nodded. “Grammatical convention also makes it look like any quoted person making a statement instead of expressing an ejaculatory exclamation or posing a question has simply trailed off, since their quoted sentence has no period at the end”.
I’m surprised that nobody’s mentioned this one yet:
Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo.
Yes, it’s gramatically correct. 
That assumes that “they” isn’t being used as the gender neutral singular pronoun, which it often is even for persons.
“IBM is going to buy our product. It says it wants…”
That sounds very awkward to my American ears. The word “it” means that IBM is a thing, and things don’t have the ability to “want.” The subject is either a group of people or a singular (corporate) person, but not a thing. Either way, the appropriate pronoun is “they.”
I think it must be some variation of Gaudere’s Law. Almost any post expressing surprise about something not being mentioned in a thread misses a previous post mentioning that thing in the thread (in this case, post number 26, where it’s even highlighted in blue and underlined as a hyperlink. 
)
True – hadn’t thought of that. Of course, that usage comes with its own problems, but it’s the best English can do for gender-neutral person, without inventing new terms. (Yeah, I know that new terms have been invented, but they’re used so rarely I don’t even know them.
Damn. Gaudere’s Law bites me again.
Not everywhere in the UK. I work for a British newspaper and our style is always to refer to companies in the singular.
So: “IBM is going to buy our product. It says it wants…”
This is even the case for companies with plural names: “British Airways has announced…”
We also always treat “none” as the singular.
BTW related to this thread: grammar that people seem to think sounds right but isn’t. I’ve lost count of the number of times I’ve heard people on TV say things like: “The reason for these changes are that…”
For some reason a plural before the verb always seems to cause it to be modified when the actual subject is singular.
The tendency to have the verb agree with the closest noun/pronoun is called proximity agreement (among other things.)