Defragmentation basically means reorganizing and in computers it comes to organizing data on hard disk in such a way that your files are accessed faster giving you an better experience. MyDefrag is a free hard disk defragmentaion software which helps you increasing hard disk speed and life.
According to MyDefrag, beginning of the hard disk are faster and if the files are sorted according to the usage ( which varies from one user to another ) and kept in the beginning part of the hard disk, it will give any user best experience when any operation is performed. Since the hard disk does less of movement in fetching data it increases its life.
This software also keeps few temporary space at various locations on disk so any files which are created on fly can be stored there instead of getting pushed at the end which will cut the performance.