5) Paid Links:
Link building is an essential SEO strategy. There are several types of links; to build quality links it requires a lot of effort and time. It is the reason most marketers take to buying links, in a bid to cut short the process.
When this is done the site owners are not interested in the content and delivering good user experience. Rather, their focus is just on placing links and influencing ranking. Google frowns a lot at paid links for no other reason. It does not deliver a good user experience. On detection, Google can lower the page rank and this will reduce your traffic.
In case you have bought links not knowing that it is wrong, the advice is that you pull them down and work dedicatedly to building quality links
6) Spam Comments
It is another deceptive way of building links. Spammer place unrelated links at the comment section of a web article. This technique is not done manually, spammers use different types of software to achieve this.
It is why you should not leave your blog open for a comment without moderation. If your blog is open to spam comment, you will be doing a great dissatisfaction to your readers. As such, you should approve your comments manually after purging out the spam comment.
7) Social Network Spamming
Posting related content and including a link to your content is good practice on social media and other networks. But posting links in social media comment section without any related content is black hat technique.
Search Engines and social media platforms can penalize you for this. Top of it you can lose the audience in this forums.
8) Doorway Pages
It is a sharp practice where marketers have many pages that leads to a specific target page. It can be a purchase page or any other page. They are pages that high rich in keyword but have low-quality content. The sole aim is to increase their organic traffic as searchers click on the link.
But users encounter low-quality content on this page but immediately directed to the targeted page. Some users will land on the target page but a good number will use the back button with few seconds.
The sole aim of these pages is to deceive search engine and move traffic from a specific point to another point. Many times both pages are unrelated in terms of content.
In the old days, Cloaking was called Bait and Switch, while the copied content you describe as one type of Poor Content was called Plagiarism.
I've always been disgusted when people do these things, and am glad to know these create a loss in the long run for the Cheaters.
Much appreciation for your articles!