The question is not entirely clear, nor can you easily find such numbers. You'd need to find the number of players, and multiply it by the average playtime per day, as an example. But I am not aware of any way (short of Blizzard supplying the info) of finding out what the average time played per day is.
a little over 137,000
To see how long you have played a character, type /played. There is no way to see how long someone on another account has been playing with out an addon, and then you both would have to have the addon.
It is estimated that humanity has collectively spent over 6 million years playing World of Warcraft and its expansions since the game was released in 2004. This is based on data tracking the total hours played by millions of players worldwide.
There are roughly 9-10 million active subscriptions for World of Warcraft.
Currently in Mists of Pandaria, the latest expansion to World of Warcraft, there are 90 levels.
The most popular war game online is World of Warcraft. World of Warcraft has been played extensively by many people since 2004 and continues to be one of the most popular games to date.
Assuming every single subscriber in World Of Warcraft plays which is ten million subscribers, then it is assumed that there are ten million people playing world of Warcraft.
It is estimated that around 9500 people join World of Warcraft every day.
too many...
There are many forums available on the official World of Warcraft website. WoW also has many "fansites" that can be found on the official website: http://www.worldofwarcraft.com Here is another website: http://www.fanaticsofwow.webs.com
World of Warcraft had approximatly 9.3 million subscribers by the end of 2007. In January (2007) they had about 8 million.
In the past couple of years, there has been about 800,000 subscriptions canceled. This leaves World of Warcraft with about 10.2 million subscribers.