I find it kind of obnoxious when other people correct my spelling or grammar in the context of blog entries. I mean, it's a freaking blog. Usually I write the entry quickly and either proofread it quickly or not at all. So I don't find it helpful to have my typos pointed out, especially if it's obvious what I meant.
I find it even more obnoxious when someone acts like a typo was made out of stupidity rather than just typing carelessly. For example, when I was doing EMGs in residency, I made the mistake of calling the "median nerve" the "medial nerve" once in a written report.
Understand that like 90% of the EMGs we do are for carpal tunnel syndrome, so you can bet I know what the median nerve is and that it's not actually called the medial nerve. And my attending, who had been working with me for weeks on dozens of studies involving the median nerve, knew that I knew that. But I sure appreciate that he acted like I didn't.
Attending: "You know, there's no medial nerve. It's the median nerve."
Me: "Oh, did I write medial nerve?"
Attending: "Yes, I just thought I should let you know there's no medial nerve. It's the median nerve."
What an ass.