Why do people always mention "I never see X on the ladder..." or "I guess I'm responsible for X's position on the usage rankings"?
The OU Ladder rankings were collected from OVER 205,000 battles in December. The most active individual battlers in Smogon might play several hundred battles, at most. Over 95% of all players play less than 100 battles in a month. On top of that, the usage numbers are based on pokemon on a team, not the pokemon appearing in battle. So you very well may have faced a team with Electivire, for example, and never saw it in the battle itself.
Any individual has a very small exposure to the overall battling sample -- certainly not enough to base statistical conclusions on personal experience. And the idea that one person's usage of Electivire (or any other top pokemon) made a dramatic impact on the overall ranking -- that's pretty silly. Electivire was used 26,701 times in December. Even if you were the most active battler in Smogon and used Electivire in every single one of your battles, you might have bumped Electivire one or two spots in the rankings. But, there are still 25,000+ other usages out there to account for Vire's popularity.
It's a different story on some of the other ladders -- but when it comes to OU play, the battle sample is large enough to be resistant to most individual oddities. It's also large enough to make most individual observations irrelevant.
I agree with this. Most people just think that percentages should be proportional, but that is obviously not always the case. If I played the same amount in December that I did in November (1000 games roughly, apparently, much to my shame) I have seen electivire several times. Do I believe that it should be OU? No. Do I believe that it is OU? Sure.
And I think Chris is taking the credit for flygon and empoleon because he wrote up the analysis of empoleon and made a thread on stark of the supposed "awesomeness" of flygon. These threads can easily influence enough players to try it out to make its usage rise notably (see colonel M's rhyperior). It's pretty much a given that if a popular player uses a Pokemon it's usage could rise, I could think of several of incidents like this.