Why does the WWE come up with different names for their participants?

World Wrestling Entertainment trademarks the names of its wrestlers, called ring names, for marketing purposes. As wrestlers develop a gimmick, their ring name becomes a recognizable brand that the WWE can use to generate interest.

Some participants, such as Sting, own the rights to their own ring name. Sting can wrestle for another promotional company and still be known as Sting. But other ring names, such as The Dudley Boyz, are owned by the WWE. When the Dudley Boyz switched to Total Nonstop Action Wrestling, they had to change their ring names to Brother Ray and Brother Devon. The WWE can still use the Dudley Boyz name with other performers and make money off of it.