"Iron forge" was a cheat code in the original Warcraft.
According to Thinking with Portals - A Memorandum on Proper Portal Usage, a book that can be found in Dalaran, Ironforge was flooded in 24 AD with water from Lakeshire when a mage removed the liquid filter from a mageportal.
Although similar to the current version, Ironforge's layout was a lot bigger in the alpha-version of the game. It consisted of multiple levels connected by bridges and stairs, two elevators (one to reach Old Ironforge, the other to reach the Deeprun Tram), an additional destination for the Deeprun Tram other than Stormwind, and a forge looking more like a power-generator than a foundry. Rumors has it there even was an elevator to the Dun Morogh airfield.
Before the addition of auction houses in all capital cities, Ironforge was THE central hub of Alliance activity. As a result of so many players in one concentrated area, the city was sometimes called "Lagforge" because of the increase in latency and decrease in framerates. Since the addition of linked auction houses in ALL capital cities, and the fact that Stormwind is located closer to the Dark Portal (for Burning Crusade) and has quicker access to Northrend (for Wrath of the Lich King), Ironforge has become much more user friendly.