Flat design is one of the main trends in the web design industry currently. This site is a based on a flat design.
Basically, flat design means doing away with all the drop shadow, embossing, gradients and textures that have been part of the web design canon for so long. Instead, flat design uses block colour and inventive typography to highlight information and functionality. Minimalism and simplicity are the key words here and the absence of distracting artifacts allows designers to focus the user on the content itself, rather than the page infrastructure.
In fact, flat design as a trend has been around for a while but several things have accelerated its use. Firstly the increasing use of high-resolution tablet displays which favour clean boundaries and graphics and can make some of the traditional design tropes, such as drop shadow, look a bit old school. The use of flat design by Microsoft for its app-based Windows 8 Metro UI has also given a big boost to its acceptance. And the widespread adoption of flat layouts in responsive web design has further blurred the distinction between desktop and mobile user interfaces.
Flat design has perhaps developed as a response to over-reliance on skeuomorphism, the use in interface design of features from real-life objects (shutter noises on smartphone cameras, calendar apps that look like desk diaries etc.) Of course, flat design doesn’t work for every application or website and it doesn’t have to be a purist thing – semi-flat or flexible flat design allows for some drop shadow or texture to be used to create a bit of distinction or help the user navigate the page.