Summary
Official Blizzard article, updated Oct 22 (date taken from the update banner): rulesets replace realm selection. Normal, PvP, Roleplaying and Hardcore (after launch) are listed, and the banner adds the Roleplay-PvP ruleset at launch on November 4. Grouping, dungeons and raids stay within one ruleset, players cannot switch rulesets without a new character, collections and Legacy Points are account-wide, and the PvP ruleset allows one faction only. Official.