SEO: top 5 list of sophisms

I recently participated to a thread in an SEO forum, and it struck me how many people in this fields are using sophism to try deceive people in thinking that they are search engines optimisation specialists.

What is sophism?
Sophism can mean two very different things: In the modern definition, a sophism is a confusing or illogical argument used for deceiving someone.
http://en.wikipedia.org/wiki/Sophism

Examples of sophism
"Whatever exists or does not exist exists"
http://plato.stanford.edu/entries/richard-sophister/

Have a look at this text from plato: http://classics.mit.edu/Plato/sophist.html
.. very similar to some SEO forums...

Sophism is used to prove something which is either not provable, or which you cannot prove yourself, or in the worst case scenario something which is actually false.

Here is a list of sophisms I came across:
1) Proving that inbound links can hurt you
'"Tries very hard to prevent site A from hurting site B" is a pretty clear indication that it certainly can happen otherwise there would be nothing to "try hard to prevent" now would there.'
Quoted from http://www.webproworld.com/google-discussion-forum/68650-can-inbound-links-really-hurt-you-2.html about whether inbound links can really hurt you or not

2) proving that you should care about keywords density
"There is much talk about the ideal keyword density of a web page. The bottomline here is that there is no thumb rule regarding the ideal keyword density in a website, mainly because the search engines change their algorithms frequently"
http://ezinearticles.com/?Keyword-Density---How-Much-Is-Too-Much?&id=401316

3) proving that you should care about duplicate content
"The solution? Don’t rely on duplicate content as your main method of driving traffic to your site. Should you avoid all duplicate content? Of course not. What kind of duplicate content is acceptable? Answering this question is easily another article in itself."
http://www.searchenginejournal.com/duplicate-content-penalty-how-to-lose-google-ranking-fast/1886/

4) proving that you should not use a dynamic site
"Dynamic Sites are Spidered Slower than Static Sites
Google in particular has made it clear dynamic sites are spidered slower than static sites. The reason for Google to do this are webmaster friendly (as I’ve recently discovered), dynamically generated sites can potentially have unlimited pages and so Google assumes a dynamic looking site (a site with URLs like dynamic-page.php?page=1) is big and slows the crawl speed. It does this to limit server load because if a dynamic site (any site) has millions of pages, Googlebot and the other spiders could cause the server to crash if they spidered too many pages at one time."
http://www.seo-consultant-services.co.uk/static-html-vs-dynamic-urls.html

5) proving that inbound links can damage your site (an other one!)
"While there are links TO your site, the majority of them are nothing more than a list of links to similar vehicle tracking sites - which are not considered to be the ultimate type of links, and in some casesis even considered a scheme or link farm, which Google specificallywarns against in Google's "Quality Guidelines - Basic principles", "Don't participate in link schemes designed to increase your site's ranking or PageRank ..." - ://www.google.com/webmasters/guidelines.htmland from Google's explanation of why your site might not be listed, "... certain actions such as ... setting up pages/ links with the sole purpose of fooling search engines may result in permanent removal from our index." - ://www.google.com/webmasters/2.html"


there are many more, but running out of time really.
http://searchengineland.com/070830-074852.php: this is a good list of SEO myths. Pick any of them, go on a SEO forum and check out what so-called specialists have to say about it - doesn't take long before digging out sophism examples -

Useful TIP: forums moderators are usually the most prolific users of sophism. That why SEO myths spread so easily.