Cleaning up a website means removing outdated content to keep the business message clear and focused on current trends, client needs, and technology. It is important for four key reasons: to maintain a clear message as the business evolves; ensure the site is responsive to mobile devices for a good user experience; help with search engine optimization as search factors include updates and responsiveness; and keep the business relevant. Benefits include increased conversions, repeat visits, search rankings, becoming an information resource, and maintaining a clear message.