This group should be the Good Grammar-Directory. Grammar-Directory is a compound-noun.

Citation-needed, because you don't get to just pull hyphenation-rules out of your-ass.

3994545
And that is why you will never qualify to be my pet.

P.S.

3994545
I disagree, on the basis that this group's name does not mean "the grammar-directory that is good" but rather "the directory of good grammar".
The former would indeed need a hyphen, but is a bunch of nonsense next to the much more logical latter (which does not require a hyphen).

3994545 Thou art shy of a convincing argument by a fair margin. Thy claim is lacking in evidence, and thou shalt find naught but scorn for thine assertions.

While a hyphen might be useful for this group's name, you unfortunately chose the wrong spot for it. If anything, it would be the Good-Grammar Directory. That is, the Directory of Good-Grammar, rather than the Grammar-Directory that is Good.

3994840

So we should make the compound adjective Good-Grammar. That works too. I thought of this group as a Grammar-Directory. I suppose that it can just be a Directory.

3994840
3994934
Guys, Good-Grammar doesn't work because it's not a compound noun: Good is an adjective and isn't combined with Grammar. While it does directly affect the meaning of Grammar, it doesn't form a compound. The hyphen is unnecessary.

This is a Directory of Good Grammar. A Good Grammar Directory, if you will.

[citation needed]

P.S. Please do tell me if you find a source that disproves what I've said. I hate nothing more than being let believe an untruth. Do provide citation, though. I know I didn't, but that's because I'm sure enough of the rule and busy enough with other things that I'm not going to waste time.

3994958
Rule 5 here: http://m.grammarbook.com/punctuation-rules/hyphens.aspx
Hyphens can change a sentence's meaning: http://www.quickanddirtytips.com/education/grammar/hyphens?page=all

Of course, in this case, using a hyphen is awkward and unnecessary. That doesn't mean we can't use one. Just that we probably shouldn't.

3995015
Agreed. I apologise for, in the first part of my response, saying that good-grammar can't be used.
As I said later on, the hyphen is unnecessary and, because of this, I would discourage it myself. That's what I meant to say all along.

Rule five of your first link could be valid, but this is the first case of confusion about the title that I've seen.
The second link is the one that really proves your point. I'll add that to my mental list of grammatical rules.

Thank you. We agree that the hyphen isn't necessary in this instance, and I managed to learn the specifics of that rule.

Good Grammar Directory it is.