Having a clear focus is important in life. It's also important in website design. Depending on what type of site you're running, how you lay things out can make all the difference between a site that works and one that doesn't. Take for example, ecommerce. If the objective is to get people to buy stuff, then anything that disrupts that process is bad.
A blank page with only a link or button, gives the user very little choice. They can either click on the link or hit the back button. So it stands to reason that the more options you put on a page can either help or hurt the objective of making a sale. In short, anything that doesn't support the objective, probably shouldn't be there.