In today's highly competitive online environment, effective search engine optimization (SEO) is essential for website visibility. While optimization methods vary widely, improper strategies can significantly hinder a site's performance rather than improve it. In this article, we identify techniques explicitly banned by search engines like Google to provide readers with knowledge on what to avoid in their SEO campaigns.

1. Hidden Text/Links
One common method involves using hidden text or links, which are designed for search engine bots but not visible to human visitors. Techniques such as making the text color identical to the background are widely used. The intent is to boost keyword relevance without affecting site aesthetics, hoping this will increase search rankings.

However, most search engines can detect these techniques and penalize websites that use them by lowering their rankings or even removing them from search results. While some侥幸 escape punishment on Google for using hidden techniques, the risks far outweigh the potential benefits. Instead, ensuring visible text content and a reasonable keyword density is a more effective strategy.

2. Misleading Descriptions of Web Pages
"Baits-and-Switch" tactics occur when a site is submitted to search engines, then replaced with different content after it's indexed. This deceptive practice involves creating an optimized page followed by a regular page upon engine ranking. These strategies are specifically designed to mislead and are strongly discouraged by search engines.

3. Misleading or Repeated Keywords
Misleading Keywords refer to arbitrary or unrelated keywords used on a webpage to attract viewers searching for related topics. One instance was a business site employing keywords such as "cartoon songs QQ love net exquisite web address body sculpting art romantic treasure volume slimming beauty..." clearly irrelevant to the website's actual content.

Repeated keywords, also known as Keyword Stuffing, involve over-the-top repetitions of keywords on pages to exploit search engines' focus on such terms in page titles and bodies. Similar tactics include keyword stuffing in metadata or employing multiple keyword meta tags for increased relevance. Engines easily detect these techniques, often meting out penalties.

4. Cloaked Pages
Cloaked pages involve hiding the actual content from either visitors or search engine bots to boost site ranking by presenting unnatural, SEO-friendly content. This deceptive practice goes against search engine guidelines and can lead to severe consequences if detected.

5. Deceptive Redirects
Deceptive redirects, often referred to as "shadow domains," abruptly redirect users to another website after entering an initial page with false or irrelevant page content. These are achieved with Meta Refresh tags and can be penalized by search engines for misguiding user traffic.

6. Doorway Pages
Doorway pages are specially designed for specific keywords to boost SEO rankings but are not useful to human visitors as they often redirect to another domain. Search engine spiders frequently ignore these pages, so they should be avoided in SEO strategies.

7. Duplicate Sites or Web Pages
Mirrored sites involve copying content from one site and distributing it across different domains and servers to fool search engines into indexing the same content multiple times. Most search engines now have filters that remove mirrored sites from their index upon detection.

8. Black Hat Link Building Techniques/Link Spamming
Black hat link-building techniques include link farms, large-scale link exchange programs, and cross-linking. These methods aim to manipulate link scores for personal gain but are easy for search engines to detect and penalize the involved websites.

9. Other deceptive tactics
Other misleading practices involve falsifying clicks on high-traffic sites to get into their toprefers log and misguiding user traffic with doorway domains. Search engines are aware of these methods and generally recommend avoiding them in SEO.

By understanding these techniques, webmasters can avoid black hat SEO tactics that can lead to penalties and improved rankings through ethical optimization practices.