Sorry to to pick on you Thomas. Some of us are sticklers for writing and grammar. Maybe that is our forte.
How do you choose who to correct?
Grammar and spelling aren't my forte, still I see many errors each and every day that go without comment.
Not to distract from the original intent of this thread, but just for conversation sake on this side issue, let me share a personal and admittedly subjective perspective.
Skill with language, or the lack of it, says a great deal about a person. I would much rather be perceived as literate than illiterate, or less than literate.
Furthermore, in this modern age, misuse of language can be a clue that an e-mail is from a dubious or nefarious source. For example, today, I received an e-note from an alleged attorney who felt he needed to alert me to some litigation he was providing for somebody with a last name similar to my own. In addition to the fact that this message arrived in my Spam, the plethora of misspelled words and inappropriate words, such as "there" being used where he should have used "they're," he had a number of sentence-fragments in his text. Those were clear signs to me that he was either totally bogus or, at the very least, not somebody I would hire for legal representation. Into the Trash his message went, without any reply from me.
Use of language tells a great deal about the document's author, IMO.
Also, regarding your question about whom one would choose to correct, criticizing others on this or any other forum for grammatical or spelling errors is not something I have ever elected to do. I would only offer criticism if it were requested, and there might be a charge for such a service. I get paid for private tutoring, or do so as a welcomed participant in an official effort, such as helping a school's principal refine a document going to the state, which has often happened in my professional career.
From my perspective, as an English teacher, I don't think criticizing others for spelling and/or grammar choices has a place here. It does not help foster a sense of community and can lead to needless friction.
FrankM.