Does Google ignore the noindex tag?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Ritchie Blogfried Pettauer: Hi everyone, I have a question about "noindex" - since when does Google ignore this tag? I just found out by chance that some of my tag pages (WordPress) have been indexed... see attached screenshot.
  
  Anybody else seen that?
• 
  Suraj Gadage: +Ritchie Blogfried Pettauer ;When did you add the 'noindex' tag on your site?
• 
  Pe lagic: View the source code of this cached (13 Apr 2014) tag page >
  
  http://webcache.googleusercontent.com/search?q=cache:cxccAcgIsmAJ:blog.datenschmutz.net/tag/tv-serien/
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  Ritchie Blogfried Pettauer: +Suraj Gadage ;- a couple of years ago, via the WPSEO Plugin. But it seems I had a temporary slip...
  
  +Pe lagic ;thx! WPSeo was deactivated only for a couple of hours (when I updated my site with a new theme) - Google is really fast these days.
  
  Thank you both so much! I'm stoked that you're so quick and so helpful. Will do my best to do the same here whenever I can.
• 
  Marcus Wong: i love this community