How not to undertake search engine optimisation and how to spot dodgy practices that will kill your site rankings
There are many good professional SEO companies around but sadly the industry is so new, and understanding of the internet in the general business community so poor, that it is still bedeviled by get-rich-quick operations which promise fast and dramatic results by using shady techniques that are likely to harm your site in the medium to long term. Here we discuss some of those techniques and how to identify if someone is offering you them or if you have previously been the victim of them.
Hidden Text
Still amazingly common, this technique simply adds lots of keyword rich text to your pages in a way that is either completely invisible or isn't easily visible to the user.
Various methods are used to hide this text. Sometimes it is simply set to the same colour as the background. If you see a large area of blank space in a page try dragging your mouse across it while holding down the mouse button. If there is text there you'll see it highlighted. If you find any on your site get rid of it immediately!
Try viewing the source code of your site. Are there any paragraphs of text there that you don't see on the page? If so they may be hidden by various means. There may be a style applied to them that makes them invisible such as display: none - this could be either in-line or via a style sheet. They could also be in an absolutely positioned div which is set to be off-screen; making it left: -1000px for instance. The idea here is that the search engines will read the text in the code and give the page more importance because of it, without cluttering up the graphics-heavy pages with all that nasty text. This is often used as a shortcut where a company doesn't want to redesign their site. However the search engines can increasingly detect this sort of disguise and will penalise you for it. Get rid of it!
Keyword Stuffing
Often closely related to hidden text, keyword stuffing attempts to further increase the appearance of keywords by inserting it in any place that it can go. ALT tags are a prime target - sometimes you will find images that have long sections of keywords added to both their alt tags and their title tags. Such tags should be used only for their proper purposes; the alt tag is there for people viewing the page with images turned off and for visually impaired people using screen readers, and it should contain enough information to tell them what the images contain and nothing more.
A similar technique is sometimes employed using the no-script tag. This is supposed to be used to show a version of the content that would normally be seen via javascript when a browser has javascript turned off. Instead some people put large quantities of text inside the no-script tag that has nothing to do with any javascript content in the hope that again the search engines will read it.
Duplicating Content
There are a number of ways that duplicate content can be used in an unethical manner. Having set up a site you can purchase another domain name and then put a copy of the same site up on that domain address. Sometimes this is done with completely different addresses and sometimes with different suffixes of the same domain - so you may have www.dodgyseo.com, www.dodgyseo.co.uk, www.dodgyseo.org etc. The idea is to have multiple sites all ranking in the top ten and squeezing out anyone else.
Again the search engines have got wise to this and if they find duplicate content then they will remove the duplicates from their indexes and may even remove the "original" if they think it was deliberate. If you have multiple sites with the same content get rid of the duplicates. If you want to use the domain names then either put up separate sites on them or point them at your main site using either DNS redirection or 301 redirects.
There is another nasty technique involving duplicate content - stealing someone else's. The unethical optimiser checks the rankings for the search term he's interested in, goes to the site that is number one, and steals their text to put on his own site in the hope that it is the text that is producing the ranking. Of course this is a clear breach of copyright. If you find that someone has stolen your text then you should threaten them with prosecution and make them remove it.
Sneaky Redirects
Doorway Pages
This technique relies on the fact that search engines have not been good at reading or following javascript. The idea is that you create a number of single page sites which are crammed to the gills with keyword rich text for the search engines but which have javascript redirects in them that take real browsers instantly to another site before the user is even aware of the text. Again the idea is to saturate the search listings with sites that all go to the same place, thus keeping out the opposition.
The search engine companies hate any attempt to show their spiders something different from that seen by the users, and of course wish to provide as wide a range of relevant results as possible, so they dislike this technique. They have now developed ways of finding such redirects as their spiders become more adept at understanding javascript, so again this technique will often be found out and penalised. If your SEO company suggests doorways pages run away as quickly as possible!