If you read the thread, it was explained. Repeatedly too, you're not the only one that didn't immediately see it...
On install, the software counts down, five days in, it attempts to authenticate, ten days in, if no authentication, poof, no work till authenticated. On authenticating, the timer is reset, giving you ten more days. Assuming constant connectivity it will re-authenticate every five days.
The problems, aside from the obvious one for someone that doesn't have internet at home.
Your isp is down, the server crashes, whatever. Shit happens and you can't authenticate when you go to play the game. It's been ten or more days since you last played the game, not exactly an unusual occurrence that. Authentication is, at this point, mandatory to play. Oops? You get to wait till you can authenticate to play.
You go on vacation/work related travel to a place with no wi-fi hotspots or land lines, assuming you authenticated right before leaving, you can play it for ten days unless you find internet connectivity somewhere to restore it.
Someone gets your cd key through a keygen(not impossible, not unheard of, very unbloody likely, but shit happens) and your authentication fails. You then get to call EA tech support(weep for humanity at this point) to straighten out your problem, it may or may not happen. The joys of having verification and disabling abused keys that may or may not have been abused by their owners.
If it's an encrypted authentication, I'd have been cut off for a couple weeks when my isp started blocking encrypted traffic for me and refused to admit it. I had to spend two full days on the phone with those pricks before I got that one past the tier 2 tech support that was still a bunch of morons reading from manuals in India. I was one step away from being sent to the executive tech support for big wigs before someone in the engineering department realized that they did indeed have a NOC controlled firewall and I wasn't full of shit when I read them their own information and told them it was shown as enabled. Tech support in India blows. Now you might be thinking big deal, play something else, but what? If this became the norm, there wouldn't be anything else. All your other games would be disabled for the same reason.
Playing without the dvd is a real winner, but I think I'd prefer to use the dvd over having it phone home every five days because I'm a thief and at any moment could up and steal the product I already bought!
It's brilliantly stupid. I'd come up with a comparison, but I honestly can't think of anything comparable.
OMG!!! THE EDIT BUTTON WAS THERE!!!
Damn you for posting before I finished typing my book! I'm such a windbag...