Hello faithful patrons,

 Keyword Stuffing:

One major "no-no" in meta-tags is stuffing as many keywords as possible into your meta tags and website with the sole intent of boosting your ranking in the search engines as opposed to creating quality content. Another common stuffing and "black-hat" technique entails creating keywords that match the background color of your web page, with the intent of hiding it from the human eye, but still allowing search engine robots to index them.

Although once popular, keyword spamming techniques can have a severe negative impact for your website. If the web indexing robots are able to detect keyword spamming, your site may be penalized with a lower ranking, or simply be removed from their index.

Doorway Pages:

Auto generated pages that are produced only for search engines to index and have no other value to the site. Doorway creation software can create hundreds of additional pages for your site in very little time, with the intent of having many pages for web robots to index. Auto created doorway pages are looked at as spam and if detected by the search engine spiders, your site will be penalized or be removed from their database.

 In some instances a website such as full on flash website may not have any choice but to create a limited number anchor pages/ doorway pages since their entire site is in a format that can not be spidered. Care should be taken in how this is rolled out.

Baiting:

Also known as cloaking. Is the use of custom scripts that detect when a particular spider is crawling/visiting your website, and auto loads preset meta tags and or content built specifically for that spider and is different content then that which actual users will see. This technique is considered search engine spam and can have a severe negative impact for your website ranking. 

Duplicating Web-Pages:

Another big "no-no" is creating multiple identical webpages or websites with identical content but different domain names. Essentially an advanced version of doorway pages. Often the websites are database driven and share the same database. Although once popular and still done by some , if web indexing robots detect duplicate sites, then both websites may be removed from their index.  

Closing Thoughts:

If you find a new hot "magic" technique for getting that #1 ranking, chances are it is a form of spam. If you get caught spamming the search engines you will likely damage your ranking or be removed from their database! The top search engine companies have some of the best minds in the business who's full time job it is to continually make their search engine better. One of the ways this is done is by improving the relevancy and quality of the database by removing sites that spam their databases. Remember most search engines such as Google have a place where people can report sites they think are spamming the search engine.   As rule of thumb, if you find a technique that attempts to artificially boost your ranking in the engines by circumventing or exploiting an algorithm that the search engines use, then it is SPAM.