Jacksonville Business Journal covers a study that claims using a multiple-monitor desktop significantly increases work productivity:
When using multi-monitor displays, participants generated 10 percent more production, were 18 percent faster in errorless production and made 33 percent fewer errors than when using a single screen. As a result, participants found it 45 percent easier to keep track of their tasks, 38 percent easier to move between sources of information and 32 percent faster to produce work.
This is an easy one. Movement stimulates the brain. Single focus on a monitor, with stationary text, is almost hypnotic. Shifting focus between two monitors is somewhat stimulating. Reading and especially viewing monitors or Tv are behaviors which involve staring, these are relatively new in human behavior.
There may be "less costly" methods to gain this type of mutiple screen stimulation. Any large or small monitor within the scope of someone can be viewed and result in eye/head movement. Even an additional shared monitor, between work stations, could display additional data and cause people to look and move. (My instinct is that a hard edge is needed to gain the head/eye movement, so a divided screen may not suffice but a second monitor would.)
A ticker could also create limited movement and stimulation. This would surely be the least costly move. A mildly predictable ticker blog could be just enough stimulation to shake the cyber hypnotism.
I don't see it as a visual stimulation issue. When I work, I need access to more information than one monitor can conveniently display -- especially when I'm writing about software or a programming process as I undertake it in another window.