Developing applications for multi-core processors will requires to introduce threading into software to allow more instructions to be executed simultaneously.
Recently, there have been articles by prominent members of the development community discussing the need for threading in applications. The problem is that we are reaching the limits of what hardware engineers can do to increase processor speed. Years ago, when processors were relatively slow and disks were small, developers spent time optimizing their applications for both speed and space. However, now processors are fast and disks are large, so most developers rely on the hardware to improve performance and worry little about disk space.