One of the biggest costs for maintaining the game was moderating the game's community by making sure that there were no obscene Lego models created by players. This meant that every single player created in-game Lego model had to be looked at and catalogued to make sure that it was age appropriate, I.E. no penises. This was to help make sure that the Lego brand remained family friendly.

One developer was almost fired when his in-game built Lego penis was discovered by a child tester during a "kid test".
Contributed by KnowledgeBase
The Grumpy Darkling appeared in promotional material for LEGO Universe, but never actually appeared in the game.
Contributed by frankfrost2
In the survival game "The Battle For Nimbus Station", the names of the four riders, Seibatsu, Ikusa, Kikin, and Shi, are the Japanese words for Conquest, War, Famine, and Death, which are the names of the four Horsemen of the Apocalypse.
Contributed by frankfrost2
There is a lot of cut content that never made it in to the game, due to its closure. Some of the more interesting cut content includes a Kingdoms World, which would have included Guilds, PvP, Mounts, Crafting,and Animal Transformations. Capture The Princess, a PvP mode that would have been added to the Kingdoms world, and would have been much like Capture the Flag, and Nexus City, a world that would have eventually surrounded Nexus Tower.
Contributed by frankfrost2
A lot of the character's names are puns based on random objects or sayings. Some of these include:

• Klaus Zett = Closet
• Numb Chuck = Nunchuck
• Wenn Wuzzit = When Was It
• Skee Daddle = Skedaddle
• Krista Clear = Crystal Clear
Contributed by frankfrost2