There are at least four different kinds of buildings in Empire Total War. Each building serves a different purpose with some serving military, some earning revenue and others promoting education. Buildings can also be used as cover and obstacles for troops as they battle through terrain.Official Site: Buildings

1. Star Fort - A military fort with an architecture that significantly helps the defense. Enemy troops have to scale obstacles and dodge bullets before getting the chance to hurt the opposition.
2. European-style tenanted farms - These buildings weren't incredibly profitable, since the demand for cattle and crops was higher than tenanted farmers. They still existed, at least until the landowners kicked them off to make more money.
3. Trading Port - Moving trading goods by land was very difficult, so things were transported by sea whenever possible. Transporting by sea also opened up more markets, since supplies could travel where roads couldn't.
4. University - These were good places to increase status and learn professions. If a person wasn't born into a high class, they could earn it if they were smart enough and could at least afford the tuition.Official Site: Buildings

• Gametrailers.com: Empire: Total War - Launch Trailer (Time: 2:00)