According to Blizzard

"In the midst of fulfilling the request that we've received from WOTLK Gold players for a long time and we're expecting there to be many new Classic players joining new players for the first-time in Wrath of the Lich King, and some of them might be worried about how they'll be feeling left out," Blizzard's forum post says. "Fresh start realms should give those players the opportunity to feel on the same level like everyone else."

There are certain rules for creating the character on a new start server.