Google's stated mission is to organize the information available to the world and make it universally accessible and useful. This is why the world's most popular search engine has been placing a lot of emphasis on delivering search results that are relevant and useful to the user. They use both refinements to their search algorithms and human quality search raters to ensure that what is shown in search results is actually what the user expected to see.
In their efforts to get the boost in traffic that comes with ranking high in Google's search results, some webmasters resort to a variety of tricks to game the search engine. While using blackhat SEO techniques that break Google's rules may have worked relatively well ten years ago, the search engine has now gotten a lot better at detecting pages that use such methods. If you use them, you'll likely end up seeing your website drop in rank or get completely deindexed.
Here are some of the most common reasons why websites are penalized by Google:
Cloaking is a technique that is essentially showing search engines a different version of your website than what human visitors get. For example, you could make your website look like it has reviews of popular books to Google, while showing pages promoting online casinos when a visitor clicks on the search result.
This is done by running scripts that detect if the visitor is a search engine spider based on their user agent or IP address.
Having a "Spammy" Website
Google has taken a serious dislike for web pages that provide a poor user experience and are against its webmaster guidelines. It considers a page to be spammy if its main purpose is to get as much search engine traffic as possible with little regard to providing any value. A page will likely be deindexed if it:
- Displays malicious behavior, like attempting to install adware or malware on the user's device.
- Has content scraped from other sources.
- Promotes affiliate offers without providing much useful content to the user.
- Has automatically generated content.
- Uses sneaky redirects or hidden links.
Using a Free Webhost
Providers of free hosting services often insert spammy ads into websites they host, which results in a poor user experience and often gets pages penalized by Google. There are also many cheap hosting providers that offer a "free" service tier with no ads. Using these hosts isn't a good idea either.
Not only do they often provide bad service with slow page load times and frequent outages, but they're also very popular among shady characters who use their services to host landing pages used in spam campaigns, phishing websites, pages tricking users into installing malware and other "garbage" content. If a provider is found to host a significant number of spammy pages on their servers, all websites hosted by them can get deindexed.
Having Bad Links Pointing to Your Website
Google's algorithm considers that the more links point to a website, the more authority it has. This has led to many webmasters using methods to manipulate Google's ranking system in the hopes of getting a quick boost in their position.
The search engine's latest algorithm updates, especially Google Penguin, now penalize websites using link building techniques that are against their webmaster guidelines. Examples of such techniques include:
- Buying links.
- Participating in link exchanges, directories or private blog network.
- Having links from blog comment or forum spam.
- Making low quality blog guest posts with links to your pages.
Providing Poor Quality Content
Google now places a lot of emphasis on content quality when ranking websites in its index. Using SEO methods that attempt to manipulate this are likely to get you penalized. The most common ones are:
- Copying content from other websites.
- Using automatically generated content or articles spinner tools that "rewrite" existing pages.
- Stuffing pages with irrelevant or repetitive keywords.
- Using hidden text.