How many players in single World of Warcraft server when it's High/Full?

Just wondering, since I haven’t seen THAT many people in a full/high servers of World of Warcraft. The question asking for both Horde/Alliance included. Can it be 1000+ players in one server?

Tips on how to make gold at low levels for Mining and Herbalism using Horde

Tips on how to make gold at low levels for Mining & Herbalism using Horde!

World of Warcraft Cataclysm Trailer **BLIZZCON 09 NEW** **Official Trailer**

The Official Trailer for the new Expansion Pack for WoW