The "www." that doesn't prefix twitter

[ScienceNerd361]

Hello all, I was just wondering why there's no "www." in the web address "http://twitter.com". Is it because "www." is just a formality at this point?

 

[johnb35]

There are a lot of websites that don't need the www in front of it.

 

[FairDoos]

tbh the "www." isnt needed at all for most popular sites its the same with "http://" that was a mistake when developed and isnt actually needed at all