Google is your friend lol. Unfortunately this forum is usually woefully misinformed.
"Play Online Right Away With In-Game Servers
All versions of Minecraft will feature in-game servers you can jump in and join right from the menu.
This includes the most basic, obvious and awesome servers at launch: Mineplex, inPVP, Lifeboat, and Cubecraft.
Minecraft: Realms is still supported, duh, and you'll be able to access your private servers from any updated version of Minecraft."