Yes, I was aware that he was talking about office and excel, etc., but I have never heard the acronym MOS. My acronym that I mentioned upthread was MOP, Microsoft Office Programs, and another fellow mentioned MOA. I guess that the OP thought that MOS would describe something even before we had to ask.
He is missing out on a lot of information if he does not log back into Tom's Hardware again, even if it is just to read and learn.