I am such a grammar nerd. 9/10 -- I don't follow any Twitter hashtags of any sort (#7), but I am totally mortified by on-line errors that I make (#5).

EDIT: I don't care about correcting anyone's Facebook pages (#2), but I do stop reading when I can't get past the writing errors - same on hubski.

Re #4: I don't actually correct public signs (at least not anymore) but I sure would like to.

I would add a #11: I like people to tell me when I make writing errors, so that I can correct them.