The definition of minimal design has never changed, and probably never will. It is truly a timeless technique.
Having said that, minimal design does seem to have evolved ever so slightly over the last few years, especially within web design. Trends, techniques and user demands have changed, and quite remarkably has resulted in alterations to the look and feel of what we would typically define as a minimal site.
Those boundaries that had previously existed between all mainstream web design trends have become blurry, resulting in a blend of styles, where only the best parts of each have been wisely selected to create a whole new minimal style.
This is the modern web. To help understand what we mean, take a look at these 50 minimally designed sites: