Then by all means, put it in the No pile.
Love it or hate it, email is the place employees spend most of their days. Good writing makes that time both shorter, and more worthwhile.
(Not to mention blogging, announcements, support materials, bugs, documentation, and meeting requests.)
Not at all... if part of the job they're applying for requires good communication skills. (And these days, even the most heads-down programmer needs that... bug reports, support docs, etc.)
That said, I think grammatical errors from an ESL speaker aren't the be-all end-all of good communication. It would really depend on what else I had to go on. Was there a cover letter? "Responsibilities" section of his/her resume?
Often extremely clear thinkers more than compensate for non-native language skills with incisive, compelling expression.
tl:dr Bad writing (communication) is just cause for putting a resume to the side. But one-off grammatical errors wouldn't be the only think I'd go on.
I don't think of it as turning to a network instead of knowing something. I think of it as turning to a network instead of Googling.
(We all look up stuff constantly. Price-checking, deadline checking, version validation, tactics, etc. We probably don't appreciate how often we do it.)
I have one staff-member who is a prominent member of a significant open source project. This person knows a LOT. So do my other staff-members. But the project member turns to his IRC window/mailing list, and gets answers really fast. Plus, he feels certain and comfortable because he typically trusts the answers he gets.
I won't say he's "better" than his peers, but this network, which he has put in a lot of work to earn, has definite value to him and us.
Though not the primary point of the article, I quite liked this line:
"Of course the tech companies are all about being paid, for doing what they do. The users are like hamsters on a treadmill. Do you ever think about paying hamsters? I don't think so!"