There are a lot of different definitions of spam from the very vague "anything that's bad" to a list of every technique that could possibly be considered to be spam. At the heart of the matter though is the engines themselves. Since they will be the ones to penalise or ban your site if what you do is what they define as spam then it stands to reason that the definition should come from them.

Unfortunately they are not completely clear on the issue either in regards to actual techniques. Probably because they feel if they spell it out exactly then the spammers will find some new way of doing it that isn't covered in the engines anti-spam list (which would probably happen).

Some people and some engines have defined spam as "anything you wouldn't do if the engines didn't exist". The problem with that definition is the conclusion that any method of trying to get good rankings, even as simple as writing keyword rich text, is spam. Try applying that logic to any other form of marketing and you'll find it just doesn't work as it rules everyone out as spammers.

But just because there isn't a list of exactly every type of spam or a clear definition of what all engines consider to be spam doesn't mean you're free to do things that have been labelled spam techniques. These include:

• Same or similar colour background/text (what some call "white text")
• Keywords on the page in a tiny font size so that it's barely readable, usually on a very similar colour background
• Stuffing the title and/or meta tags with tons of irrelevant or repeated keywords (or variations)
• Using hidden layers as a place to hide keywords
• Splash pages (ask Google - they said it, not me)
• Multiple, machine generated or very similar doorways, sometimes full of nonsensical jibberish with keywords scattered at "strategic" locations throughout to come up with a "perfect keyword density" for a particular engine
• Mirror domains and homepage (or whole sites)
• Pages that redirect a viewer to a page on a different topic (you search for and find what you think is a baby clothes site only to be redirected to one about motorcycles)
• Cloaking and IP delivery (a tailored page is served to and indexed by the spider but the viewer sees the real site)

Bear in mind that some of the above techniques are employed with no thought to search engine positioning. For example:

• IP delivery is used by some engines to redirect regional users to their regional databases
• A lot of companies are left with domains and sites after mergers that they mirror or redirect to their parent company's site
• Hundreds of sites have splash pages despite the fact that Google has publicly stated that they consider it to be a form of spam
• Some sites are simply badly designed and end up using tiny text or similar text/background colours

It does appear that the engines make exceptions in some cases but all of the above do raise "red flags" and may very well cause your site to be penalised or banned. Just because another site used it without any harm to their listings doesn't mean you will be able to. Life isn't always fair and the engines are not answerable to you. So to be safe avoid all appearance of evil and don't do spam.

Search Engines' Spam Policies Pages:
Google Webmaster Section: Dos and Don'ts
Google Webmaster Section: Facts and Fiction
FAST Alltheweb Spam Policy
Inktomi's Content Policy - Spam Removal Guidelines
AltaVista Advanced Search Tutorial - Being Well Indexed

Articles from SEO Experts on the Issue of Spam:
Desperately Seeking Search Engine Marketing Standards
BruceClay.com Emerging Standards
White Paper: Relevancy, Spam, Technology, Cloaking and Ranking
To Cloak or Not to Cloak
Cloaking: Search Engines Shift Gears

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