The main idea behind grid-based designs is a solid visual and structural balance of web-sites you can create with them. Sophisticated layout structures offer more flexibility and enhance the visual experience of visitors. In fact, users can easier follow the consistency of the page, while developers can update the layout in a well thought-out, consistent way. However, it’s quite hard to find your way through all the theory behind grid systems: it isn’t easy at all. Some important notions and related key-facts can help to learn basics and keep essential techniques in mind.
Link: Smashing Magazine