For general directories that we never asked to be listed on... is it a good idea to use the disavow tool for these types of links even if we haven't received any kind of penalty from Google?
I would never use it if you haven't got a penalty. My gut feeling is Google knows about those auto-scraper sites way more it does about link networks (which could be something to worry about).
By the way, here is a nice post about how to tell if you need to use the disavow tool at all http://www.link-assistant.com/blog/t...efore-disavow/
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