Generally speaking, correcting other people's grammar online is something I only do if asked (such as reviewing something), or if the individual is needlessly jumping on someone else's grammar while making mistakes of their own. Since this is an informal setting, where people often type as they speak, grammatical issues, or issues with syntax, organization, or the overuse of colloquialisms doesn't bother me. The only stipulation is when someone types in such a manner where it's nearly impossible to comprehend what that person wrote, without reading the post over and over and over again, all the while making assumptions as to what that individual is saying.
Additionally, I don't care to type with perfect grammar. I use tumblr a lot, and my habit for typing on there is "like this usually ignoring capitalization, sometimes punctuation, since for some reason everyone there understands me when i type like this and it's just a habit i picked up there." Then again, most people I know on tumblr are personal friends who pretty much know me, so there's no desire to present myself in any other way.
