Giant FAQ answering random questions I copied off the official forums:
1) A cluster of cities in the 16 city region are connected by road, but they can connect by other means of transportation.
2) Police Precinct's detective wing needs a university with a school of law, and a completed research project.
3) After placing a University in a city, high tech industry will show up.
4) When you build a university, you can do research projects to unlock modules on other buildings.
5) Roads connect a cluster of 4 cities, but each cluster can be connected by rail/ferry (if available).
6) Trains travel from city to city.
7) Sims in the region can commute to other city for school.
8] You have a finite amount of resources, so once you run out, that's it.
9) Rail cannot transfer electricity, just roads.
10) It is possible to have an entire city full of industry, but only a certain amount of sims will commute. You can get more sims to commute by adding public transportation.
11) The Expo Center, Pro Stadium and a few others will come with a list of events to choose from. As the sims make their way to the event you will see just how many showed up, and how much you made from the event(s).
12) Multiple servers are in for launch. They are separate from each other for everything, but you can use anyone you want and more than one.
13) Too many henchman equals LOTS of crime.
14) ProTip: If your citizens are educated, definitely go with nuclear power!
15) To effectively send gifts, even money, be sure to have good traffic flow into and out of your cities.
16) Suggestion: Make a loop through your city with a big avenue and keep intersections with it low. Cross streets too!
17) It is NOT possible to destroy a Great Work. Once they are constructed, they are permanent.
18] You cannot control Dr. Vu's machine. The machine will shoot things with lasers and missiles, and Maxis Man will try to fight him off.
19) Each region has different limits on the amount of players. The maximum is 16 players.
20) Trees do help with pollution, but will slowly die if your city is polluted.
21) You can not only add modules to buildings, but you can also remove them too using the bulldozer.
22) You can use the Ctrl key on your keyboard to quickly place zones along the edges of roads.
23) The secret to maximizing city size is road layout.
24) You can bulldoze everything in the city or go to region view and claim other cities to build.
25) If your internet goes down while you're playing, you will still be able to play for a short period of time. No specific time frame has been given!
26) In the final version of the game, you will be able to see spacing requirements for roads to help you build your city.
27) The "rapid" means of transportation are: buses, trains, boats, planes and streetcars.
28] The tutorial that we saw during the beta is the same, but there will be other tutorials in the game to help you.
29) Sims will use transit all over the region, they do not use planes though. Will have to get more information on this!
30) You can mix zones to help maximize sims overall happiness.
31) Lot sizes are automatically generated by the game engine.
32) Radiation turns into ground pollution.
33) There are no glowing ground effects for radiation, you can only see it in the data layer.
34) Ground pollution will slowly heal itself, but it will take a long time.
35) You can limit your building growth by keeping your roads at low capacity.
36) Emergency vehicles will only be stuck in traffic in single lane roads, if a lane is free the vehicles will move out of the way for the emergency.
37) Your cities/regions are only available on the first server you sign up on, but you can sign up on the European server and play there.
38] You, and other mayors will need to be on the same server to play together.
39) Each server has its own global economy, and does not affect economies on other servers.
40) You can upgrade roads to increase building density.
41) You can trade with other cities.
42) You will not be able to change the height of the roads, this feature may present itself at a later time.
43) Cheat codes are available in sandbox mode only.
44) Cheat codes can provide money, toggle fires, disasters, crime, etc.
45) A meltdown is caused by cutting off education.