Years ago, when I interned at Microsoft, they did a company survey to figure out what to name what would become Vista. The top two names were Windows Hooker and Windows Heroin. True story.
I can only imagine someone trying to explain the logic on this one in some ad copy somewhere. "TSO" is the kind of name that requires its own FAQ entry just to explain, and even then it doesn't make sense.
Sometimes a story that explains a name can help spread it - provided it's funny, interesting or an otherwise
memorable viral vector. TSO might not qualify.
i actually liked "MEGA". the acronym was meh, but "Microsoft Mega" has a nice ring to it. probably would have gotten some flack at release (sega mega drive, etc) but overall i think the best out of those listed.