D-BUS is a system for low-latency, low-overhead, easy to use interprocess
communication (IPC). In more detail:

  o D-BUS is low-latency because it is designed to avoid round trips and
    allow asynchronous operation, much like the X protocol.

  o D-BUS is low-overhead because it uses a binary protocol, and does not
    have to convert to and from a text format such as XML. Because D-BUS is
    intended for potentially high-resolution same-machine IPC, not primarily
    for Internet IPC, this is an interesting optimization.

  o D-BUS is easy to use because it works in terms of messages rather than
    byte streams, and automatically handles a lot of the hard IPC issues.
    Also, the D-BUS library is designed to be wrapped in a way that lets
    developers use their framework's existing object/type system, rather
    than learning a new one specifically for IPC.