Microsoft has popularized the metro design trend with the release of its flagship operating system Windows 8. Basically, metro UI design is characterized by its reliance on fonts or typography and as opposed to graphic elements. On the surface, you will notice that metro style websites have big, catchy texts in flat solid colors. This is the defining feature of metro design technique. This is considered by Microsoft as a respite from the icon based UI designs that has been prevalent in the web.
minimalist websites Archive
Right now, flat website designs are all around the web and its popularity does not appear to be declining. Basically, flat websites tend to be simple, clear and straightforward as opposed to intricate realism advocated by skeuomorphism. Instead of beveled edges, gradients, shadows, reflections and realistic textures, flat websites use solid colors, simple typography, icons and UI elements. Rather than exude a three-dimensional effect on its interface elements, a lot of flat web designs employ parallax scrolling and visual clarity to draw the audience.