MultiFract texture can be generally described as a "roughness" texture.  Adjusting the parameters will change the appearance of the texture in a wide variety of ways.

Parameters :

Position : Position of the texture.

Scale : The texture is scaled by this value.  Use these parameters to scale or stretch the texture in one or more directions.

Twist : This is an adjustment to the noise applied to the texture.  The higher the value here the more tightly "wound" the noise becomes.

Continuity : Higher value here makes the texture more continuous.  Lower values will make the texture more and more fragmented.

Granularity : This parameter controls how "gritty" the texture is.

Notes : This texture makes a nice stone surface, particularly if scaled in one direction.  Also concrete or tile roughness.