There are many different ways people can encounter a 404 error on your website. But, many of the 404s visitors encounter on the web result from link rot. What exactly is link rot and how do you defend your site from it?
Link rot results from old, outdated links that have long since stopped working. The page the link took you to was removed years ago from the web. Much like those leftovers you forgot to throw away in your fridge, that old link has grown moldy and is doing more harm than good.
Link rot is inevitable on the web, though. Web pages will change often and other pages will be removed. That is good site management—pages should be removed and pages should be changed.
But, as those pages change or are removed the links across the web that referenced those pages will break. The bookmarks in your browser that referenced those pages will break. The links in your email that referenced those pages will break. The links referencing those pages in that ebook you downloaded last year will break. The longer those links remain broken, the more rotten they will become.
You want to avoid rotten links leading to 404 errors on your site. Chances are, though, that if your site has been around for more than a few years, you do you have a rotten link problem. At some point, you removed a page from your website or moved a page to a different URL. In doing so, you broke the links referencing that page. Don't feel bad, it happens on every website.
How do you identify this problem and prevent it in the future? Here is a quick rundown of how to prevent the links referencing your site turning rotten.
Let's say, for example, you removed an old blog post from your website. Using a monitoring tool, you notice that over a hundred people came to your website looking for that old blog post in the last week. Instead of finding that 404 error, those visitors found a 404 not found error instead. In digging into it, you find that the people who reached that 404 error did so because of a link on your local newspaper's website.
In that example, it would probably be important enough to put that old blog post back up. You don't want over a hundred visitors per week reaching a 404 error on your website. You also don't want an important link from your local newspaper's website to grow rotten and hurt your website in the process.
If you don't want to put that blog post back up (or can't), you might want to find another blog post to redirect that old blog post to. That way when those hundreds of visitors each week click on the link on your local newspaper's website looking for that old blog post, they are taken to a newer, related blog post instead of a 404 error.