Yep, I've been following this guy and I would've watched his stream to see him ding 90 on Saturday if we hadn't been busy. That is some serious dedication, I would say at least as much as the WoW Ironman competition.
Pandaren are the new faction for the latest xpac, Mists of Pandaria. In order to make the content new for everyone including folks who rerolled panda they created a split faction of the pandaren with the story that a bunch of them got on the back of a giant floating turtle many generations ago and have been traveling the world ever since. If you roll a Pandaren you start out on this island not knowing anyone hence being neutral (any other race you are automatically Horde or Alliance based on that race). Blizzard laid it out so you level to 10 on the island, meet the Horde and Alliance, learn a bit about each and then in order to leave the island you choose a faction and are sent to that faction's main city as an ambassador. If you don't pick a faction you don't get to leave. The faction choice is permanent and pandaren who choose the opposite faction are hostiles you can't talk to just like any other character of the opposing faction.
Doubleagent was getting 30-40 experience points for every herb he picked or node he mined (which he had to walk around and find because he couldn't train riding and there's no mount vendor on the starting island). The first few levels don't need many points to ding a new level but the experience points required increases as you get higher. By the time he was lvl 70 he needed over one million points per level to ding. So that's 15 million experience points just to get from 70 to 80. And he could only get 30-40 at a time.
Took a quick look at WoW Wiki and according to the current formulas it takes 26,106,500 points to get from 1 to 80. And then it's 22,180,300 to get from 80 to 85. Not sure what the math is to get from 85 to 90, it's probably in the 25-30 million range.
Doubleagent has quite a following on the forums, I imagine there was quite a party there this weekend. Some folks have followed in his footsteps, it'll be interesting to see if there's ever a significant number of people that manage to pull it off.
“The movies will always be what brought us to this place, but these other stories kept us there. Most people just visited Star Wars. Fans that obsessed over the Expanded Universe lived there.” Phil Owen