Wireframing can be one of the most important tools for establishing clear usability and clarity of content.
When reviewing design work, it's very easy to be 'blinded by the pinstripes' - you can see something absolutely beautiful that is barely usable and doesn't fill the needs of the application.
Wireframing strips away all the stlyle and tricks, and boils the website down to its core purpose. What is the content we're trying to get across to the user? Does that content make sense and can it be navigated?