Broken links are links that lead to pages that do not exist. When clicking on a broken link, the page you land on is called a 404 error page, a standard HTTP response that indicates that the requested URL doesn’t exist.

What do you do when you happily surf the web and suddenly come across a 404 error? For most of us, the immediate response would be to simply leave the current site in favor of another one because both people and search engines consider broken links as unprofessional.

404 errors and broken links also have negative effects on your search engine rankings so it is quite reasonable to be proactive in avoiding them to improve exposure and increase site traffic.

via How to Find and Remove Broken Links in Your Website.