Using multiple processes rather than threads. Use sockets to connect between different processes (very difficult though, and have to use TCP to prevent packet losses- which may not be suitable for real-time applications like skype) However, using multiple processes means you can run the software with multiple computers that are connected in the network (whether it is connected to private or public network), and this is much more powerful than a single process with multiple threads (which can only run in a single computer). This is a concept of distributed computing.