Originally Posted by
Lime
I think it's genius. They stopped reporting it while their MMO was deemed as the most popular subscription MMO.
What this means is that if WoW ever drops low enough and another MMO becomes more popular, most people would likely not know. It'd allow them to maintain the illusion that they're still the king even if their actual numbers say otherwise. If WoW drops to 3m and lets say, purely as an example, FF14 jumped to 4m, many WoW players would still think that WoW has more because they last reported it at 5m, so they don't have any other number to go off of.
Having your fans state "This is the most popular MMO" is still great publicity.
Now, I'm not saying this is the reason they did it, but it's definitely a plus for them.