Sometimes people vanish out of the Google index and don’t know why. Usually, they come to an search engine optimization (SEO) company like ours when they want to find out. Over the past few years, we have discovered several common inadvertent (or advertant “worked at the time) “black hat” techniques that tripped people up in the search engines.

What is “black hat SEO? For the uninitiated, “black hat” refers to practices that are designed to get rankings in the search engines by using unapproved or unethical methods. The usual goal of this type of optimization is to get high rankings for popular search terms, then monetize the traffic that comes in, regardless of the site’s relevance. In the early days of search engines, it was common for webmasters to trick people by placing irrelevant sites into search engine results. Many of the sites presented had adult themes which were not requested by the user. Part of Google’s early credibility came from the fact that it presented results that were relevant and screened for such content.

This list is by no means exhaustive, but here are some obvious black hat techniques:

1. Doorway pages. This one is an oldie but a goodie. Every once in awhile we still see a series of small dots at the bottom of a page that are linked to little pages with keyword stuffed content. These little pages forward back to landing pages on your site. This technique has been out of favor for several years.
2. Keyword stuffing. Also a classic. Once upon a time, people would repeat the name “Britney Spears” several thousand times at the bottom of a website. (As a testament to the popularity of Ms. Spears, she is still a top search term 10 years later.) People also repeat the same keywords in content to the extent that it is obviously meant for search engines.
3. Auto-generated content. There are quite a few programs that will scramble or “spin” content from scraped sources or sample paragraphs. This “spun” content then gets placed on hundreds of web pages. There is no substitute for original content. Search engines do not want to waste bandwidth indexing bad sites, so they have an incentive to remove your site from the index if you have a series of sentences with no logical grammatical flow.
4. Cloaking. Does your website present different content to a search engine than you present to a viewer? If so, you may be guilty of cloaking. Search engines consider this to be a “trick” so you can get penalized if you get caught. It is possible to get tripped up in this penalty if you are making adjustments for browser usability, so be careful.
5. Hidden text. There are different ways of hiding text. One is to use coding tricks to make the text visible to the search engine but completely invisible on the page. This can be done with “noscript” or “noframes” tags, CSS, and other source code machinations that make the text infinitely tiny or “miles away” from the page content. Alternatively, you can make the text color the same color as the background. Search engines are good at detecting this, even if the colors are not exact. Honest site owners can get filtered for hidden text if their content is too close to the color of the background.

Here are some SEO practices that can get you in trouble:

1. Link Exchanges (or reciprocation). If you have had a website for any amount of time, you probably get poorly written link exchange emails. There is no point in answering them, as they are automated. This is a practice that went from white hat to grey hat to black hat. It probably won’t get you banned, but you won’t get any value from the links, which is just as bad when you’re buying them.
2. Buying links from spammy sites. There are lots of people out there who will overcharge for bad links. Usually, they add you to a list of sites which have a very large number of links. If all of the links to you have the same anchor text, you can see search results for that anchor start to slide in the search engines.
3. Affiliate Content. If you’re selling products that have the same descriptions, part numbers, and other information as those on dozens of other sites, you are walking a fine line. Furthermore, if you are linking to known affiliate sites, you can be penalized based on the nature of the links. Search engines like original content that adds value, so the only way around this is to create fresh content (like user reviews) that links to affiliates in a search engine friendly way.
4. Duplicate Content and Domains. In some cases people will have .com, .net. and .org sites with the exact same content on each. This was misused in the past, so now only one domain gets credit for content in search engines. Alternatively, people put the same content on different domains hoping to dominate all the search queries for a keyword. We have even had customers who take our optimization and put it on multiple sites, and learn that the results can’t be duplicated.
5. Selling links in a non-discreet fashion. If you’re monetizing your site with obvious paid links, search engines can usually tell. Usually paid links are in their own little spot like a box or column on the right or left margin. Search engines have a much harder time figuring out if the links inside text blocks are paid, unless you’re running a blog that has low-quality outbound links on every posting. If you are buying ads on other sites for the traffic, you may want to look into using the “nofollow” command.
6. Linking to bad neighborhoods or “black hat” sites. Normally this happens when someone doing SEO on your behalf decides to give some of your link popularity to other sites, or even to their own site. You are responsible for the links on your site, so if you link to questionable content, you may get hurt. If you trade links with a site that is no good, you may suffer for it. If you have had multiple hands on your site over the past few years, it is a good idea to find out where all the links are going.

There are two kinds of SEO penalties. The first, a “filter” will create an artificially low ranking on search engine results until it is fixed and acknowledged by the search engine. The second, known as a “penalty” or “ban” will take you out of the listings completely. This can happen for a variety of reasons. We have even seen one case where someone had an Amazon affiliate page that was competing with the homepage (one was index.htm, the other index.html) and the site was taken out of the index. A notice in Google Webmaster Tools acknowledged a violation of guidelines.

How do you know what else to avoid? No discussion of black hat methods would be complete without a link to Google’s Guidelines which help the average user create a site that avoids the obvious issues.

Can you benefit from black hat techniques? Maybe. A common story from potential customers goes as follows: we used a technique that we knew was “wrong” and we shot up to the top of the search engine, then we vanished. Therefore, if your goal is to get traffic for a brief amount of time, or you have the ability to create a cascading chain of websites that get banned in short order, you may be able to profit from black hat techniques. Then again, some of the best practitioners of the “dark arts” are in Eastern Europe and Asia, and they have been at it for years, so you may have a steep learning curve ahead. Meanwhile, white hat search engine optimization lasts longer and gains trust year-over-year, which is the long-term strategy preferred by the majority of our customers.