From a British perspective, I think 'Hi everyone', but 'Dear all' sound the most natural.

As for capitalisation, according to The Gregg Reference Manual, which I understand is pretty influential in American business and professional circles, all nouns in the salutation should be capitalised, but not 'everyone' and 'all', because they are pronouns. This would be in line with the rules for headlines in, for example, the New York Times.

@Chris B - Thank for the compliment. Well, you're the first person to notice the dont's, which I'm afraid is a mistake (I'd like to say misprint!) , and one which I seem to have repeated several times.I meant, of course, "Do's and don'ts". So thanks for pointing that out; I've now amended it and given credit where credit's due.

Personally I find 'dos' looks a bit strange without an apostrophe, and prefer to distinguish the first from, as well as your examples - DOS (Microsoft). But once you've done that, I don't find an extra apostrophe is necessary in don'ts. Probably totally illogical, but that's how I like writing it.

This is one of those areas where I think you have a choice, unless you are following a particular house style. I don't personally use apostrophes with capitals and decades, but have no problem with those who do.

What really annoys me, though, is those 'think-they-know-it-all' people who mock others for their 'apostrophe abuse', while themselves apparently being pretty ignorant of the (relatively short) history of the apostrophe. For example, at one time, the so-called greengrocer's apostrophe was quite respectable - this is from Alexander Pope's Epistle to Dr Arbuthnot, quoted without comment in Dr Johnson's Dictionary - 'Comma's and points they set exactly right' - http://books.google.pl/books?id=IYQUAAAAQAAJ&printsec=frontcover&dq=pope+epistle+to+dr+arbuthnot&hl=en&sa=X&ei=vV0DUrHbJIrEPciUgNAN&redir_esc=y#v=onepage&q=comma%27s&f=false

@dave - sorry but I don't agree. I'm British and I often say things like 'If it wasn't for the such-and-such, I'd do such-and-such'. In fact, the subjunctive is used rather more in the States than in Britain; we very rarely use present subjunctive, for example - 'it is very important that this be finished by Friday'.

I teach British English to foreign learners, and all our course materials recognise both 'was' and 'were' for hypothetical use, with 'were' being seen as more formal.

Look at all the nonsense written on the Internet about Joan Osborne's 'One of Us', because it includes the line 'If God was one of us'. Most of the objections to this line seem to come from America. What's more most of the grammar websites that say 'were' is the only correct version are American. (Although to be fair, so are most of the linguistics sites which say that this is nonsense).

And there's a good reason for this. My understanding is that more Americans learn grammar at school. Between the late sixties and the early nineties there was hardly any grammar taught in British state schools as a reaction against the conservatism of grammar teaching at that time . As a result, my impression is that there are a lot more people in the States who consider themselves as grammar geeks than there are in the UK. But on the other hand the grammar they learned at school and put forward on forums etc, often tends to be quite conservative (or perhaps better - formal).

Check out Grammar Girl, one of the less dogmatic American websites, and you'll find that she only accepts 'were', in hypothetical situations. - http://www.quickanddirtytips.com/education/grammar/subjunctive-verbs?page=all

On the other hand 'If I was' is regularly used by highly educated British English speakers, as you can see if you read my blog post, linked to above, which grew out of another thread on this website on the same subject.

@jayles - I think Northern English dialect use of 'were', as in 'He were in t'pub' (He was in the pub) is a bit of a red herring here, as it has nothing to do with the subjunctive or hypothetical situations, but is a non-standard indicative verb form, just as Northerners might also say 'We was on our way to see our Valda', and some Londoners might say 'I done it yesterday, didn't I?'

I presume Missy Sosler is talking about a hypothetical conditional regarding the present /future, in which case the traditional purist 'correct' version is to use the subjunctive, which in this case would be 'were'', for example 'If the current owner were allowed to have an auto body shop, he would open one tomorrow'.

However, in almost all verb forms the subjunctive past is exactly the same as the indicative past:

'If the current owners were allowed to have an auto body shop, they would open one tomorrow' - no difference
'If the current owner wanted to have an auto body shop, he would open one tomorrow' - also no difference.

So, not surprisingly many people, especially perhaps in Britain, no longer make this differentiation, and use the indicative 'was'. Modern linguists and many modern grammarians (for example in EFL/ESL teaching) consider both to be correct, the only difference being in formality. Personally I use both, as the fancy takes me, and if anyone tells you that 'was' is wrong here, I'm afraid they are rather out of touch with modern grammatical thinking. This use of both subjunctive and indicative past for hypothetical or unlikely situations is known in EFL/ESL teaching as 'the unreal past' , and in at least one modern grammar reference book, as 'irrealis'.

I've written about this at some length here - http://random-idea-english.blogspot.com/2011/11/subjunctive-were-revisited-again.html

Perhaps it's time to blow my own trumpet - http://random-idea-english.blogspot.com/2011/01/dos-and-donts-of-apostrophe-use.html

@bubbha - and a lot of American commentators will swear blind that this is set in stone, so if writing for an American audience, it's perhaps better to stick to it. But this is rather an artificial rule and a relatively new distinction (see my comment above). In Britain we've more or less eliminated the problem by using further for everything - farther is pretty rare nowadays in British English.

As to your other point; yes, we need an edit button.

@Chris B - it probably depends on who the people are. I'm not so sure about spelling, which is a bit more fixed, but if enough educated speakers of Standard English use a word or phrase a certain way, and the dictionaries, which reflect usage, pick it up, and if enough other educated speakers accept it, yes that will make it correct.

That's why addressing a single person as 'you' rather than 'thee' or 'thou' is correct. This came out of usage, not grammar books, and this usage was simply picked up by the grammars. That's how English formed, after all (except for the dictionaries).

Incidentally, according to Bryan Garner, while this is regarded as a colloquialism in the US, it is a standard idiom in Britain, a point the British etymologist Michael Quinion at World Wide Words agrees with.

@DC Howard - I don't want to knock you, because I broadly agree with you as regards usage, but I'm puzzled by one or two things. If something is idiomatically acceptable, how can it be 'not strictly correct', or do you perhaps mean it is inappropriate in formal language. And I wonder who decides when something is 'allowed'.

Most of us use formal English very rarely, so I'm puzzled why some people think that what is appropriate for formal language is the only thing that can be 'correct'. How can something that is OK in informal (i.e. normal) language be 'not correct'?

Normal language as used, for example, by the editorial board of the New York Times - "The government went so far as to try and convict a dead man for tax evasion" (Mr. Putin Tries to Crush Another Rival - July 18, 2013

And by a staff writer at the Guardian - "in its biggest initiative to date to try and convince marketers to branch beyond TV advertising." (Mark Sweeney 20 June 2013 - despite the Guardian Style Guide's injunction - "never 'try and' "!)

And a correspondent for the Telegraph, in an article title - "Brazil president Dilma Rousseff proposes referendum on political reforms to try and quell protests" (Donna Bowater - 25 Jun 2013)

And from an academic essay (2011) by Tessa Humphrys (at Google Books) - "Did the UK government use PR to try and win hearts and minds in the run up to the Iraq war? If so, how successful was this?"

And the British leader of the opposition, Edward Miliband, quoted on BBC News - : "People who try and divide us will fail"

And BBC News itself - "A Nene Clinical Commissioning Group (NCCG) spokeswoman said it planned to meet Labour councillors on Thursday to try and answer their concerns."

It's interesting that in nearly all those examples "try" is part of a "to" infinitive; perhaps the writers were unconsciously trying to avoid a double 'to' - "to try to". What's more we can't use it as a universal substitute for "try to". We can say "to try and" and "will try and", but "trying and" just don't work, and neither do past forms.

Merriam-Webster Dictionary of English Usage points out that it has been socially acceptable for two centuries ,and has been common in print for a century and a half, although it admits that it is not used in an 'elevated style'. When was the last time any one of us wrote in an elevated style, I wonder?

Several people have quoted Fowler, but not I think this bit (First Edition) -"It (try and ) is, therefore colloquial, if that means specially appropriate to actual speech; but not if colloquial means below the proper standard of literary dignity." He then suggests that "try and do" has "a shade of meaning that justifies its existence".

@aragond - I'm used to grammar lectures on this forum, but for a joke? It's not meant to be proper English. It's a play on words and is totally improper English! See my previous comment.

On my keyboard (no separate numerical pad) , there is a ^ sign above the 6. So I just do - shift + 6 + e - which gives me ê. As simple as that.