Recently, Blizzard announced they will be changing their Blizzard client name to Blizzard Battlenet,because it represents years of shared history and enjoyment, community and friendship amongst the players and the Developers
“Battle.net is the central nervous system for Blizzard games and the connective tissue that has brought Blizzard players together since 1996. The technology was never going away, but after giving the branding change further consideration and also hearing your feedback, we’re in agreement that the name should stay as well. Take it from the developer formerly known as Silicon & Synapse, and Chaos Studios, names are important too.”
source here