Blizzard have just announced that starting with Tuesday's 1.0.3 update, that newly-purchased copies of the digital version of Diablo III will be held back to Starter Editions for up to 72 hours. Blizzard says that digital purchases now require a review period before being completely unlocked in order to combat fraud and other illicit activities.
The reasons behind this aren't exactly clear, but it could be something as obvious as Blizzard trying to stop banned players from quickly getting back into the game, and could help filter out gold sellers and other spammers. Other reasons could be that fraudsters are purchasing the game and cancelling before the funds clear. Naughty, naughty.
Diablo III's Starter Edition limits players to Act I of the game, with a 13-level cap. Matchmaking is only supported with other Starter Edition players, with no access to the gold and real money auction houses, Global Play is also unavailable. This might piss some people off, but the people who have pumped hours, days, and weeks into the game are now a bit safer.