There's been a lot of talk in this thread about the advantages of close city placement; can someone elaborate on the disadvantages? What do you give up by spreading your cities out?
The huge buff to specialists between Civ 3 and Civ 4 makes close city placement much more attractive, but there must still be advantages to taking the alternate strategy.
Yes, it's quite frequent that 0 inconvenients to overlap are mentioned.
That would be because completely avoiding overlap is an equally frequent beginner's mistake (so people only sell the good points).
Inconvenients to overlap:
1- For the same cost in settlers, you hold less territory (resources?) and, assuming you're not isolated, rivals hold more.
2- If one expands a little far, he then has the option to backfill. Settling all cities with max overlap in the very beginning is a sure way to find oneself boxed in.
3- Assuming the territory held is the same, then overlapping cities has higher costs in buildings (Granaries, Forges, etc.) and maintenance.
4- Assuming one wants a super-city (hosting a National Wonder? Capital?), then it might not be the best idea to share the food. This is a weak point: one can overlap and yet leave the stronger tiles to the stronger city. But overlapping to work only weak tiles is a weak idea by itself...
Stronger points:
1- Sharing the food. Typically (assuming Granary), the city that is lower in size wants to work the food (because it costs less to grow a size).
2- Developping cottages. Cottages don't develop if they aren't worked, so having 2-3 cities sharing a cottage tile is a sure way to work it at all times.
Conditions:
1- One has to manage the tiles. If several cities share the same tiles, then the right city has to work the right tile.