It can mean several things, IMO. I'll list a few:
1. Person has social anxiety
2. Person feels uncomfortable (for whatever reason) and feels more comfortable looking elsewhere
3. Person believes its rude to make eye contact, or other cultural stigma
4. Person is distracted by his/her own thoughts or something in their environment
5. Person has bad hearing and watches your lips move to help understand what is being said
Most of the time I try and make eye contact with others when I talk to them, as I feel it expresses to the person I'm speaking to that I'm paying attention to the conversation, and because it tends to hold their attention better as well. I also feel that without looking at least at a person's face while talking with them, certain things get misunderstood or lose some meaning.
The eyes can be a window into someone's soul, though some are very good at giving nothing away. I always make eye contact with people when I'm out, especially if I'm in a club, at a party, or a concert. I use to bounce at a pretty rough rap club in downtown Sac, and the head bouncer, a hispanic powerlifter named, "Bam," had gotten so good at reading people's eyes he could predict two times out of three who would be a problem for us later on, just by making eye contact with them at the door.
In the pen...nevermind
