I just launched a Stack Exchange site dedicated to language (grammar, etymology, translation, etc.). I have not really advertised it so far (apart from a post on HN ).
Can you come up with some original marketing ideas for that type of site? I was thinking of running a small AdWords campaign and see if it works (but that isn't exactly original). My goal here is to get a couple of early adopters and grow the community from there.
First of all use the power of the SO platform.
Create a set of questions that a lot of people are asking on google. That way you will figure high early on.
I have said it before but it's still a good way to create a good set of popular questions.
go to google suggest and type in words or sentences related to grammar.
I just did with Comma
Then create a set of questions based on that and answer them. Should help you quickly gain some traction.
I would also launch a twitter account with grammer rule of the day or something along those lines. Something fun for people to subscribe to without it being too spammy.
Remember we are connecting more and more based on actual interest rather than marketing. So if you want to attract people be interesting.
Also see if you can get access to places like oDesk that have thousands of copywriters, editors etc. from all around the world.
And if you are doing doing podcast as also suggested find interesting things to talk about that is not necessarily about language but perhaps about people who work with language.
For instance check out Wordy.com they translate your blog posts within one and a half hour directly in your blog.
The grammar girl has a podcast. You should probably consider doing the same.