Google is very choosy about the kind of content you are putting up on your pages for SEO. If they suspect that you are indulging in these Black hat techniques for content optimization, they are surely going to blacklist your site.
Here are some things you should take care not to include in your content strategy.
This is basically a lack of enough content to populate your pages. For example, if a large percentage of the pages on your site consist of a few lines of content, it will raise a Google red flag.
Sites that simply collect content from other sites without any original content of their own are marked down by search engines.
While some syndicated content is perfectly fine as a way to backlink, a greater portion of your site consisting of syndicated content from third parties is considered black hat by Google.
Scraping content from other sites is the same as stolen content or plagiarism. If you are copying articles from other sites to publish onto your own, you will be charged with scarping content by Google.
These are a stealthy way to get more traffic. Basically, these pages are intended to simply route search engine traffic to push sales. These pages are often a misfit with the other pages on a site and purely meant for the purpose of driving quick conversion.
E-commerce sites with manufacturer-supplied descriptions
Low-grade e-commerce sites will not get a content specialist to write optimized content for them. Instead, they post plagiarized content by using the same product descriptions as supplied by the manufacturer to describe their product line.
User generated content (unmoderated)
User generated content is almost always low value content. While enabling users to write comments and reviews can be a very helpful in enhancing the trust rankings of your site, you should get the content reviewed before allowing it to go live.