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There's no way to tell for sure, since changing something like that in history is a lot more significant than the typical "crush a bug" or "accidentally kill your ancestor" kind of stuff with comical Michael J. Fox results.

I'd say, if it was taken seriously and steam-powered machines were developed soon after 100 AD, that doesn't necessarily mean that everything else happens sooner... Mankind could very well be stuck in a rut for a thousand years of steam technology, only ever making slight improvements when the occasional genius comes by and invents a new way to utilize steam. They'd probably have steam cars, steam boats, steam factories and whatnot (assuming there is enough effort put in to understanding the chemistry and physics involved), but it would probably only replace horse-drawn-carts, sails, and man-power until someone eventually harnessed electricity or at least advanced mechanics (like the difference engine and stuff) to make REAL progress.

I'd say that definitely the medieval, feudal, and renaissance eras of Europe probably wouldn't even occur, since steam powered machines would likely replace the need for man-and-horse farming. I'd imagine a steam powered printing press would make literacy and education more widespread and at a much earlier time, but unless someone actually discovers how things like electricity and petroleum work (which are more left up to chance than flat out research), there's no guarantee that any modern technology would develop any sooner, but it might be more likely.

Man... 100 AD. It's hard to even think of machinery that long ago. In 100 AD, things like bricks and wheelbarrows were just becoming common (mass produced bricks, I believe, not the hand-made adobe type stuff). If nothing else it'd make a great setting for a book or graphic novel.

I could see how this could EASILY be made into a motor... If the torque is made powerful enough, you could turn the sides of the ball into sprockets and have it pull a chain (or just pulley/rope or wheel/belt combos) and accomplish some basic stuff like maybe operating a grinding wheel or small mill or something, and eventually they'd figure out something more usefull.
Hero's Aeolipile (the steam ball)
http://en.wikipedia.org/wiki/Steam_ball

I don't think there was a government in that sense back then. They had like kings and rulers who could impose as many unfair taxes as they wanted. they could tax water even. I think more likely it was ahead of its time and its potential just went over their heads.