  This article reviews the unconventional effects of random disorder on
magnetic quantum phase transitions, focusing on a number of new experimental
and theoretical developments during the last three years. On the theory side,
we address smeared quantum phase transitions tuned by changing the chemical
composition, for example in alloys of the type A$_{1-x}$B$_x$. We also discuss
how the interplay of order parameter conservation and overdamped dynamics leads
to enhanced quantum Griffiths singularities in disordered metallic
ferromagnets. Finally, we discuss a semiclassical theory of transport
properties in quantum Griffiths phases. Experimental examples include the
ruthenates Sr$_{1-x}$Ca$_x$RuO$_3$ and (Sr$_{1-x}$Ca$_x$)$_3$Ru$_2$O$_7$ as
well as Ba(Fe$_{1-x}$Mn$_x$)$_2$As$_2$.
