I'm planning two more:
Where do you live? (continent/sub divided for popular areas)
How many characters do you have rolled at one time? (1, 2, 3, 4+)
Take the second poll and make an average, then use the current number of pfiles (there's a command for that) and crunch them. You'll get a guesstimate of total players on the mud.
If you want to guess at how many different people total, it's going to be many more times those that haunt Dioxides. So definetly closer to 300, but how many more I couldn't say.
Yhorian