Google have indexed 300k **tag pages** of my site, these are automatically generated based on the words on the title of each entry so it's likely to see pages which doesn't make much sense like:

```
www.example.com/tags/thanks.html 
www.example.com/tags/hello.html 
www.example.com/tags/good.html 

```

After reading [this answer](https://webmasters.stackexchange.com/a/67078/53722) by @John Mueller i suppose that Google would be able to detect duplicate content and show the better version in SERPS, but my fear is the 'low quality' and 'thin content' of these pages and the possibility of a sitewide effect due to Panda.

[![Organic traffic for tag pages](https://i.stack.imgur.com/FHHFa.jpg)](https://i.stack.imgur.com/FHHFa.jpg)

I'm getting 8000 daily visitors from organic traffic for the tag pages (that is 3% of site traffic)

Would it be a good practice if i put a noindex in order to prevent a penalty and help Googlebot to not waste time crawling?