I thought this SimCity wasn't online only, but required an online connection to start, but doesn't need to persistently be there. Not sure that's an important distinction, but some seem to care.
I disagree with everyone claiming the online is shoe-horned in, anyway. I know that, during my glory days of SimCity 2000, I would have loved the option to build a city next to my friends' cities. It's limited, but the ability to send more crime or the occasional tsunami to them would make it all worthwhile to me.