Let's see if I can remember...
Resources like coal, rubber, and the like do not show up on the map until you have the scientific advancement that allows you to use them- also some continents are just completely without certain resources, which makes it a good idea to station colonies on resources early on in the game before others snatch them up.
They left out quite a few things in Civ III- some wonders just can't be built any more, and there are no more wonder videos- too sad because they were one of my favorite features from Civ II! I don't know if they thought all the neat animation was excessive, or that they were making a trade off by including the animated faces... ? Too bad, but it is still a cool game, and runs smoothly enough.
I can't quite remember, but you might have to have a road connecting you to the other players capital before you can build an embassy- someone correct me if I'm wrong, it's been a while since I played...