Google’s algorithms may be a black box, but its Webmaster Guidelines are meant to leave little room for speculation, yet some gray area remains. While the guidelines are written in easy-to-use language and outline some of the illicit practices that may lead to a site being removed entirely from the Google index or otherwise impacted by an algorithmic or manual spam action, there are no real-word examples, albeit for good reason.

Here are past and present examples of how to get your website banned by Google overnight.

1. Participate in Link Schemes

Any links intended to manipulate a site’s ranking in Google search results may be considered a link scheme, as was the case in 2011, when the New York Times uncovered a link-building scheme by J.C. Penney. The retailer ranked number one for bedding, dresses, area rugs, and other vague and specific keywords, with “uncanny regularity” for several months. After consulting with an industry expert, the New York Times found 2,015 pages with phrases like “casual dresses,” “evening dresses,” “little black dress” or “cocktail dress,” which all bounced directly to the main page for dresses on JCPenney.com.

NYT excerpt: There are links to JCPenney.com’s dresses page on sites about diseases, cameras, cars, dogs, aluminum sheets, travel, snoring, diamond drills, bathroom tiles, hotel furniture, online games, commodities, fishing, Adobe Flash, glass shower doors, jokes and dentists — and the list goes on.

J.C. Penney said they did not authorize and were not involved or aware of the posting of links that the New York Times sent to them. J.C. Penney immediately fired their SEO agency, but not before Google took manual action against the brand for violating its guidelines. Overnight, J.C. Penney was vanished from search results for anything other than branded keywords (a.k.a. direct searches for J.C. Penney). It took about three months for J.C. Penney to move up the rankings and regain lost rankings.

2. Include Doorway Pages

Google defines doorway pages as those that are large sets of poor-quality pages where each page is optimized for a specific keyword or phrase. Google always frowns upon manipulating search engines and deceiving users. In 2006, BMW suffered Google’s wrath for setting up doorway pages to attract search engines and redirect traffic to its German website, BMW.de. BMW’s page rank was reduced to zero. While BMW stated it did not intend to deceive users, the company added, “However, if Google says all doorway pages are illegal we have to take this into consideration.”

3. Sell Links that Pass PageRank

Selling links that pass PageRank violates Google’s quality guidelines; this includes advertorial pages with embedded links that pass PageRank. Google recently penalized Interflora, even removing it from branded search results, for using advertorials to solely influence search rankings. An example of this, is that Interflora reportedly sent bloggers floral arrangements in exchange for links. This was once considered a gray area, but is clearly black hat now.

4. Scrape Content

In 2012, Google blacklisted a network of websites run by the family of U.K. Parliament member Grant Shapps after the search giant found the sites breached rules on copyright infringement and that they were based on scraped content. This latter black-hat tactic is typically when webmasters use content from other sites to try to increase credibility and the volume of pages.

According to Shapps’s spokesman (as reported by the Guardian UK), the Parliament member “is quite simply not involved in this business.” Certainly, it was avoidable bad press nonetheless.

5. Use a “Bad” Blog Network

If your site belongs to a blog network whose purpose is to create backlinks, Google will de-index them and penalize you. In 2012, this happened to Build My Rank, which ultimately closed down and relaunched as HP Backlinks. The relaunch, however, has many people wondering if (and when) Google will go after the network again.