Is simplicity the best way to ensure usability?
It can often seem like there's a straight line between simplicity and usability. Improving usability and user experience involves working to reduce confusion, and the simpler something is, the less confusion there can be. If an object (or website) is simple, it's immediately apparent how to use it. The more complexity you introduce, the more difficult that becomes, and so ‘keep it simple’ can seem like a solid usability rule of thumb.