The simplest is just talking in the in-game General Chat channel which can be accessed by typing '/1' and then whatever you want to say.
While playing, there are several ways to make friends. The simplest is just talking in the in-game General Chat channel which can be accessed by typing '/1' and then whatever you want to say. Trade chat, though intended for exchanging goods and services, also ends up being a pretty lively channel and can be accessed by typing '/2'.