Allow me to confirm that the loose coupling comment is about modularity. Two pieces of code are tightly coupled if there are complex interconnections between them. They are loosely coupled if they interact through well-defined interfaces that expose very little of the internals.

A large system built of loosely coupled pieces is generally going to be much more reliable, maintainable, etc than one which is built in a tightly coupled fashion. Therefore loose coupling is generally a good thing. Code Complete has lots more to say on this topic.