Characters
The leaderboards rank the Inferno clear times of every region's boss stage (stage 7; Spire Hill Crypt Lower: stage 3), plus the Mythic Rift, with a tab per hero. Online characters take part in them.
Character slots
The main menu has two tabs, "Singleplayer" and "Online"; each tab shows 4 character slots, and a fifth character of a type is refused ("You can have at most 4 characters of this type"). A name has 1 to 24 characters once the spaces at both ends are trimmed ("Name cannot be empty", "Name must be 24 characters or fewer"). Singleplayer characters cannot use the leaderboards or Market Trading; creating one asks first:
"Singleplayer characters cannot use social features such as Leaderboards and Market Trading. Continue?"
"Online characters can participate in leaderboard, trading and other social features. Stable network is required for the best experience. Violating online policy could result in ban."
Online characters need a Steam account that owns the game. A shared or borrowed copy can only play Singleplayer: "Online Mode requires your own copy of the game. Steam Family Sharing, Free Weekend and PC café licenses can only be played offline."
"Only online characters can trade." The Auction House is for online characters only.
Online characters cannot buy equipment or treasure chests in a shop ("Gear can't be bought on online characters", "Chests can't be bought on online characters"). They can buy Mystery items, at the price the game server sets.
Auction House items that are withdrawn or claimed arrive in the mailbox: "Withdrawing or claiming sends the item to your mailbox after a short cooldown."
Storage, gold, materials, Life Skills, unlocked minions and Paragon.
Statistics
The Statistics panel counts Total Play Time, Total Gold Earned, Total EXP Earned, Deaths and the loot found of each rarity.