With increasingly accurate data on RR Lyrae stars we find that the Blazhko effect may be a rule rather than an exception. However, we still do not know what is the cause of this mysterious amplitude and phase modulation. In this talk, I intend to give a glimpse of the properties of Blazhko stars, presenting recent findings (including Kepler's) concerning what makes Blazhko stars different from their non-modulated counterparts.