Many people think that not found errors (what we focus on here at SpringTrax) are a technical problem. After all, a not found error means something on your website broke. While it is true that not found errors do represent a technical problem, it is important to remember that a not found error isn't just a technical problem.
What a not found error really is, is a usability problem. A usability problem is an error that prevents a person from using your website.
There are all kinds of usability problems. If your shopping cart is clunky and slow, that is a usability problem. If people are unable to use the search tool on your website, that is a usability problem.
Not found errors are a usability problem as well. Why?
The obvious reason for a not found error being a usability problem is that a not found error blocks a user from using your website. Your website couldn't find what that person wanted to find. That creates a roadblock or a dead end that keeps people from continuing through your website.
That is part of it, but there is more to it than that. There are ways to remove the roadblocks and dead ends from your not found error page.
So, what really makes a not found error a usability problem?
People see that your website broke. To that person, your website is now associated with an error.
If that person only encountered one error, they might forgive you (or forget) and move along on your website. However, if your website returns multiple errors to that same person, that person will associate your website with errors and avoid your website (and, possibly, avoid your entire online presence).
Ultimately, it is all about perception. If people perceive your website is broken, then it is broken even if technically there really isn't anything wrong. This negative perception is what causes the error ripple effect that keeps people away from your website and costs your company customers.
What can you do about it? Certainly, you want to minimize the frustration people feel when they reach an error. That helps people deal with the error. But, even if you make the errors as simple as possible, people will still perceive your website as broken when they see an error.
As a result, the only way to limit the number of people who have this negative perception of your website, is to find every not found error your visitors encounter and fix your website's errors as quickly as possible.