What should I do if the “noindex” attribute doesn’t appear to be working?

Matt's answer:

MATT CUTTS: Today’s question comes from Alex in Montreal. Alex asks, hi Matt, I’ve been having issues with the no index attribute. In some instances I placed the attribute to block a page but it still seems to get indexed. Even when the page is cached with the no index attribute, the page is not disappear. Thoughts? Great question, Alex. I answered another webmaster video question with a somewhat similar answer, which is if you see something like this, that seems like it’s a clear bug in our robots.txt text or our noindex handling, or we’re treating a web pages as if it’s a video, or something where you can grab a screen shot or point to a particular link an so and show this is really a bug, that’s a perfect time to show up in our Google webmaster forum. Which is linked to from google.com/webmasters. Now with your particular question, I’ve actually seen one thing like this happen before. You used the word no index twice in your question. And you put a space in both times. And I think noindex should have no space in it. So I’ve seen at least one person in the past who they actually had some spam. And I pointed it out to them. And they said, oh no, how did you know about that? I was supposed to use the noindex so you could never see that spam. And I said, well you forgot and you put a space in the noindex tag. So it could be that that’s what’s causing the problem. If it’s not, no matter what, if you see something that looks like a clear, clear bug, that’s a great time to show up. Leave a question the webmaster forum. And then sometimes people can instantly point out, oh maybe you misspelled noindex, or added a space in, or here’s the strange thing. But either way, that’s a great way to help diagnose and debug those sorts of situations.

by Matt Cutts - Google's Head of Search Quality Team

Original video: