a comma question - I know, it depends.

I know this will depend on the style guide, but mine is strangely silent on this topic (or more likely, I'm crap at finding the information in the book).  So I'm wondering what you guys think.

If I sign a communication, saying thank you and then my name, I would often put:

blablabla
Thank you, R.

But what if I want to start the email by thanking someone else?  For example:

Thank you Bob, that is just what I needed to know.

To my mind, there would not be a comma between "thank you" and "Bob" because the thank you is acting both as an expression of gratitude and a stand-in for "dear".  I don't start a letter like this:

Dear, Bob,

That would be weird.

And yet, every spelling and grammar checker HATES me for saying "thank you bob,"  Multiple error messages and often autocorrections to put the comma between thank you and the name.

Is it just the Canadian in me that feels starting a sentence with "thank you person, and more words on the subject" is a normal way to start a sentence?

Just mildly bemused this morning, procrastinating, and thought this might be meaningless enough to post in the drivel form as comma placement always has lively discussion.

(for those who are curious, I use a variation on the Oxford Canadian style guide - with a emphasis on the UK side)

Is that the bloody serial comma?  

I would not use the additional comma in your example.  

Somewhere, you'll probably be able to find a rule that states indeed, a comma is proper there.

With that said, similar to a proper place setting at the dinner table, the salad fork goes RIGHT THERE, the teacup & saucer goes RIGHT THERE, etc., it's a guideline.  A recommendation.  

Thank you Bob, at the beginning, is correct.
Grammar check thinks you are using it at the end to sign it, so that use would be wrong.
One of the limitations of grammar check, it ignores too much context.  

Mrs. Washenfelder would say, always a comma after thank you.

I would also start "Thank you Bob, ..." I agree the spellcheck thinks you are ending "Thank you, Bob" where Bob is your name. It may not be right but I was taught to read the sentence, if you pause then there should be a comma if you don't pause there shouldn't be one.

I'm inclined to think that, although I would do as you R and just put

Thank you Bob,

at the start of a message that this is technically incorrect.

I found a website grammarhow that sort of explains the rule, and it is to do with whether you can remove part of the sentence. 'Thank you' is shortened from 'I thank you' which is a complete sentence.
So we could say

I thank Paul for creating Permies Forum

thank you for creating Permies forum

or

Thank you, Paul, for creating Permies forum

So

Thank you, Paul,

clear as mud right?!

What I learned is that when addressing someone directly, their name/title is always separated from the rest of the sentence with a comma or commas. The classic example of why it's important to do this is

Let's eat Grandma.
Vs
Let's eat, Grandma.

The salutation in a letter is an exception. The comma separating the person being addressed is excluded, but the salutation is on its own line. So your example could read

Thank you Bob,
That is just what I needed to know.
Or
Thank you, Bob, that is just what I needed to know.

The second version would be incorrect because it's a run-on sentence, though. You'd need to connect the two somehow, like, "Thank you, Bob, because that's just what I needed." That sounds pretty awkward, though. Maybe change the structure entirely to, "Thank you, Bob, for giving me the information I needed."  I'd just go with the salutation on its own line.

Just posting to say, as a descriptive linguist, I see commas, everywhere, whenever, anyone, feels, like, u,s,i,n,g, them ,,, and I think it's hilarious and I enjoy it,

r ranson wrote:
But what if I want to start the email by thanking someone else?  For example:

Thank you Bob, that is just what I needed to know.
...
And yet, every spelling and grammar checker HATES me for saying "thank you bob,"  Multiple error messages and often autocorrections to put the comma between thank you and the name.

Is it just the Canadian in me that feels starting a sentence with "thank you person, and more words on the subject" is a normal way to start a sentence?

"Thank you Bob" and "that is just what I needed to know" are both independent clauses. That means they stand alone as sentences and when you connect them with a comma, the error is called a comma splice.

So the most obvious "fix" is this:
Thank you Bob. That is just what I needed to know.

But also, see what your grammar-checker thinks of these:

Thank you Bob -- that is just what I needed to know.
or
Thank you Bob; that is just what I needed to know.

(I'm personally unclear on how "proper" those are but I use those constructs to avoid comma splicing.)

I'd also be curious what your grammar tool thinks of that opening if you line-break after that comma and start a paragraph with the second clause.

(All the usual caveats are in place -- this is your (our) language and you can use it how you like. It's only "wrong" in my book when it slows down communication for no good reason -- and poesy is a good reason. But from the context it seems like you're exploring how to comport with the group-expectations of how the language is used.)

Google said, To add a "thank you" salutation, integrate phrases like "With sincere gratitude," "Many thanks," or "I appreciate it" before your closing, choosing a level of formality appropriate for the recipient. You can use a warmer, more informal tone for friends, or a more formal one like "With deep respect" for business contacts

I usually just sign my name in closing so I like to keep it simple so I would just say Thanks, then sign my name below that.

So the most obvious "fix" is this:
Thank you Bob. That is just what I needed to know.

The spellcheckers do not accept that solution (although personally, I agree it's the obvious one)

Same error messages and autocorrect woes due to the lack of comma after "thank you".

I have an MS in English with a concentration in linguistics.   My position is that the purpose of language is to communicate. For every day purposes, it don’t matter…as long as you are communicating what you intended to communicate.  Now if you need to write a formal letter, that can be a little different.

Jan White wrote:What I learned is that when addressing someone directly, their name/title is always separated from the rest of the sentence with a comma or commas. The classic example of why it's important to do this is

Let's eat Grandma.
Vs
Let's eat, Grandma.

This example particularly shows the issue. Eating Grandma is cannibalism and not approved of where I live. The comma clarifies what the intent is - like the old joke that "Pandas eat, shoots, and leaves." vs "Pandas eat shoots and leaves." where the word "shoots" switches from a noun to a verb based on the comma.

Thank you Bob. That is just what I needed to know.

To me, this would only be fully corrected if you added the comma after thank you:
Thank you, Bob. That is just what I needed to know.

I don't always have names for these things, but Christopher identified it as a "comma splice" - using a comma to mash what should be two sentences into one.

Ultimately, though, English defies rigid rules because there are just too many versions of it out there!

My mother in law was a legal secretary for many years.

Her advise was not to worry about commas or any other punctuation except the period at the end, if needed.

For maximum clarity thou shouldst say “Thank thee, O Bob”, ensuring the proper use of the singular “thee”, so that thou referest not to multiplicitous personae. The comma in this case is very natural. Whenever addressing someone thou shalt use the word “O” before their name; however, this would be unnecessary and confusing when positioned before thine own name.

In all seriousness I am with you on “Thank you Bob”. I feel like beginning with “Thank you, Bob” feels slightly more stilted and maybe a little robotic sounding. It doesn’t follow the natural pattern of speech, at least as I have heard it. The latter makes me think of a schoolteacher standing before the class, enunciating the comma.

If someone said/wrote to me, “Thank you M” then I would probably take it better than “Thank you, M”. The latter sounds almost a very little bit like someone is talking down to me. A question of register rather than correctness. It might be different for other people, though.

I like “Let’s eat Grandma” as a yardstick, too. Can it be misinterpreted so egregiously as that? If not you’re probably fine.