Quote Originally Posted by Edax View Post
Player interest will congest the servers, player apathy will cause the population to dwindle. Probably after 3-4 weeks, the congestion should go down as the power-players have already maxed everything and got bored.
Pretty much this. When an expac drops they generally institute the AFK timer as well and set aside secondary instances to handle the increased load. Generally it works out pretty well with a few notable exceptions such as Raubahn and Pippin 'Savage'. However those issues were a case of two specific instances not being ablt to admit everyone who wanted in, rather than entire data centers buckling under the strain.