When your SimCity cities get established, at a certain point you may cast your gaze toward the Great Work site in your region. I believe every region has a Great Work site, which is designed to be a collaborative project between you and the other players (if any) who share your region.
The city I'm trying to grow as large as possible has been crippled lately by gridlock. Traffic isn't just an annoyance, it can cause serious issues for your tiny townsfolk. You can get a readout on traffic by clicking on the Roads menu. This will give you a color-coded overlay of the traffic situation in your town. Green is okay, yellow is a problem, and red means "bad traffic."
Last week I had a blast playing SimCity, but I guess I was one of the lucky folks who always wants to play when the rest of the world is off doing things other than gaming.
In the wake of SimCity's disastrous first week, the game has been pulled from Amazon due to too many complaints from users unable to log into EA's servers to play.
Not counting SimCity Societies, which many players feel is "not canon" and not really part of the series, the last time we got a new SimCity game was 2003's release of SimCity 4. It was pretty mind-blowing at the time, I remember being briefly lured away from the Sims franchise to play it.