We all love a good 404 Error page. Whilst sometimes being used as an opportunity to get a cheap laugh or to poke fun at their own website, 404 error pages actually carry out a really important task. 

When a 404 status is returned (slightly different from a 404 error page itself) it tells search engines that the page is no longer available. This is important for sites that remove content - as most sites will do, at some point. 

Setting a 404 error and leaving it "live" for a while will, over time, cause search engines to drop the page out of their index, if it was indeed indexed. 404 error's are usually reserved for pages where there isn't much SEO value, and they're happy for the page to drop off any index - otherwise a 301 redirect would be the better status, whereby the user (or search crawler) would be taken to the next most appropriate page on the site.

Have you found a great example of a 404 error page live on the web? Submit it below and if we think its worthy of inclusion here on this page you'll be credited with sharing the page.