The Wall Street Journal had a nice succinct article on the front page of their their "B" section about Navteq and Tele Atlas..
Catch it if you can pick up a copy today (sorry it's already late) or have an online subscription --
Who Keeps Digital Maps Going in Right Direction?
If you miss it and you're still interested, send me a Private Message with your e-mail address and I can try to forward you a copy through WSJ.com's "E-mail this article.." interface.
"Tele Atlas and Navteq spent more than two decades building databases of information that the European Commission now call a "duopoly market for navigable digital maps." To get an idea of how hard it would be for a new entrant in the business, consider their process: The companies dispatch hundreds of field personnel around the world to drive millions of miles of roads at slow speeds and log every detail, from major landmarks to speed-limits and one-way streets. Both companies combine those data with other sources like aerial photos and satellite imagery."
also... regarding one of the data collectors and a quote... "his job is never done. "The goal is to make the data match reality 100%," he says. "That's unrealistic, because the ground reality is always changing, but we try to keep up."