I've just finished a class using WebCT for trade calculations.  In this class, I have a 
number of students working at their own pace on a number of different objectives.  This 
can lead me to any number of situations.

One young man is busy on FaceBook rather than doing his course work.  Another young 
lady seems right offended when I point out errors that she's making.  Another woman in 
the class is single with 4 children.  While she's got a good attitude, she's exhausted.  I 
had to wake her up twice from a sound sleep.  At one point she's drooling on her shirt!

While Computer Assisted Learning (CAL) is, in my view, ideal for this course as its focus 
is drill and practice, having your students wandering in all directions requires a 
completely different class management style.