No, it's not a course in English and there is no forum requirement.
We all make a variety of mistakes and/or typos.
However, it is good general advice to watch the presenation of your ideas as well as the actual content. No one is immune to being subtlely influenced by a poor presentation and thinking worse of the presenter even if the ideas are very good. I don't worry about making some mistakes (and, for sure, don't even see them all
) but too many look sloppy and careless.
Some people take the precaution of entering longer posts in a text processor of some sort. You can get an annoying "internal server error" just when you submit a lot of work. This can have the side effect of spell checking for you. I, obviously, rarely bother.
In other words, no matter what is explicitly said -- spelling
always counts. Just some advice.