Battle.net

Battle.net was the first online gaming service incorporated directly into the games that make use of it, in contrast to the external interfaces used by the other online services at the time. This feature, along with ease of account creations and the absence of member fees, caused Battle.net to become popular among gamers and became a major selling point for Diablo and subsequent Blizzard games. Since the successful launch of Battle.net, many companies have published online game services mimicking Blizzard's service package and the user interface