This is the first post after a while, and we’re trying to have more than one post every two years. But let’s be honest, you’re not interested in this yadda yadda anyway and just came here because Google Webmaster Tools sent you a kind message like
Increase in not found errors
Then you went to GWT and saw an unexpected spike in 404 (or 410 where Google doesn’t make a difference) like this one:
The total amount of course varies from case to case as Google sends the warning if an unusual increase happens. However the numbers can be as high as hundreds of thousands not found pages.
And then you immediately thought “What’s wrong? Will this harm my rankings?”
You surely stumbled across the official post that confirmed that it won’t harm your rankings in most cases.
So you’re kind of safe now, but you want to know what caused the spike and how to get rid of the errors? Well I can’t tell you what your problem was, but I’ll show you mine and maybe, just maybe, it’s the same
To put it simple: you shouldn’t.
Here’s a short explanation why: By all means returning a 404 in this case it the right thing to do, but a rising amount of 404 in your webmaster tools console and a weekly warning message just don’t feel right. The immediate thought usually is to block the URLs via robots.txt. But that’s the wrong thing to do for two reasons:
- You tell Google that there is a page existing (which isn’t) and it’s just not allowed to crawl
- You move the 404 errors to the “blocked URLs” section of your webmaster tools
But why believe me? I could just fool around with you, couldn’t I? Well no, I spent some time researching on this topic and came across an official answer by a Google employee: see the initial thread on Google Groups and the follow up question on stackoverflow
Now have fun redirecting!