10. Can't stick their heads out of Windows
9. Fetch command not available on all platforms.
8. Too difficult to "mark" every website they visit.
7. Involuntary tail wagging is dead. Giveaway they're browsing www (dot) pethouse (dot) com instead of working.
6. Keep bruising noses trying to catch that MPEG Frisbee.
5. Still trying to come up with an "emoticon" that signifies tail-wagging.
4. Three words: Carpal Paw Syndrome.
3. SIT and STAY were hard enough, GREP and AWK are out of the question!
2. Saliva-coated mouse gets mighty difficult to maneuver.

and the Number 1 Reason Dogs Do Not Use Computers...

1. Butt-sniffing more direct and less deceiving than online chat rooms.