1. – Relying on Meta Tags – This has to be number one because its effectiveness has reduced month on month for the past few years. Don’t get me wrong, they are still important … just not for the same reasons they used to be.
Although opinion is spread about the keywords tag and it’s use, for those in doubt use them, and even if not in doubt still use them, some search engines still rely on them!
As for the Description tag is an important tag because although not used directly to improve your search rank, it is used in search results by most search engines, along with the page title, to give the search engine user and idea of what can be found on a specific page.

2. – Purchasing Links – Please do not think by this I mean you should not advertise or sponsor another site for the means of traffic, what I am meaning is that buying links within text on a website should be thought about carefully for the following reasons (this is not an exhaustive list):

• Search Engines have things called spiders/robots. As well as reporting back about your site and it’s content they also report back on certain areas and keywords found such as “Ad”, “Advert” and “Sponsor” etc.  It is believed that any links surrounding this will have no effect and will not be used for any kind of search engine ranking system.
• Google accepts report of paid linking (as do other search engines) and all reports are passed on to thier team of experts.
• Google has a large team in Asia who’s specific task is to look for (and at) paid linking, flagging any possible paid links, making it useless for the purpose of SEO (though this isn’t to say they do not drive traffic to your site).
• If a search engine finds that you are amongst the thousands always paying for links, a part of the pattern which they search for to show such a thing up they can and will ban your site, either on a permanent or temporary basis.
• Get only Meaningful Links

3. – Keyword Stuffing - This can be one of the most damaging aspects of content for a website. Spiders will report back on keyword density (amongst other things). If your site is found to have a density of above 15% it will be considered that you are keyword stuffing. Your site will then be reviewed and possibly face the same banning issues as for paid links. However if your site has a density of over 30% you are likely to face an immediate ban. The ideal density is around 7%.

4. – Invisible Text – This is text which a user cannot see, but a search engine can. It is normally hidden -9999px off a page or is disguised by being the same colour as the background. In truth this is easy to spot not least because if you perform such a (black hat) trick, you are likely to never have made a website and therefore perform the action directly in the code. However, even if its hidden in external CSS you can be certain this will have be spidered, meaning search engines know your site layout and will now look out for the attribute id’s and class names that may standout.

5. – Duplicate Content – This is normally done in one of three ways. Duplicate Websites this is normally where a company has 2 websites for the same selling purpose but with different marketing strategies. Doorway Pages / Links this is where two or more sites by the same company have “covert links” between themselves, this is to say one “about us” page may lead to the information on another site. Blog NOPP this is where a blog post does not use Old Post Promotion techniques (such as link backs with excerpts) but rather copies the whole post (making it appear like a new post), its quite easy to find two pages exactly the same on a site for a search engine.

6. – Session ID’s in the URL – if you have looked carefully at the make-up of a URL sometimes you will see the ending of .com/?user=$xxq343?$/somepagename this shows a user id (or session id) this almost always renders SEO useless as each session has a new ID which means the page a spider finds will not (in theory) exist when a user clicks on the search results. It is also a way of tricking search engines into always thinking you have new pages, so they will treat your site as bad and using black hat techniques if you do this.

7. – Using Flash - It may look pretty but it really isn’t. It is still considered fairly useless for search ranking, even though both Google and Yahoo have worked with Adobe to open each SWF file for the use of search engines (this is still very very primitive). You would be far more better advised to use Microsoft SilverLight as it has been built with the ability for the MSN search engine (live) to spider it fully.

8. – Too much JavaScript – Again looks pretty but too much spoils the broth. It works very well on most sites but you should consider graceful degradation of your design to ensure your site can be spidered by websites, this is often as simple as implementing it using call-in scripts (includes).

9. – Cloaking - Now as it sounds this is showing one thing to one person and another to another, well almost, its more you show search engines everything they want, and then show users something else (normally something filled with adverts and useless content). Primarily used by spammers several years ago, and still for the same reason used now it is very powerful….until you get caught. And your site gets an immediate ban!

10. Not admitting your mistakes - if you find that your site is banned or isn’t doing well, or simply can’t be found and you suspect bad SEO, contact the search engine, tell them the problem and the reasons for it. By admitting an issue most search engines will release your site form a ban as long as you can prove that you have no intent to be banned for the same reasons again.

Other actions which don’t quite make the Top 10!
Ill considered URL changing – Incorrect removal of pages – Poor Content (content with no value) – robots(txt) incorrect or non-existent – bad country targeting – doorway pages – no internal links (or lack of) – use of internal CSS (causing to much html tagging, aka wasting indexing time) – no 404 pages – no sitemap – large pages (+100kb) – bad theming

So that just about wraps it up, I invite you too add your own point to my list in the comments and/or ask questions about my list.

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Destroying Your SEO Efforts – Top 10 was written by Andy Kinsey and published on SEOAndy.com SEOAndy.com is an internet marketing blog where you can find free hints and tips to improve your SEO strategy. SEOAndy.com is part of Andy Kinsey Designs, Andy is a designer and marketer from Manchester. Visit http://andykinsey.co.uk