Search engine optimization (SEO) is a complex and diverse topic that's both never constant and constantly changing. There are hundreds of myths about SEO, some were once true but no longer apply (outdated information), while others were simply never true to begin with (disinformation).
The large amount of different opinions and tactics used by both Web Designers and SEO Consultants (which can be completely contrasting) has also helped to create myths. Combine this with the large number of web forums and blogs that allow people to share their views, and you have the perfect environment for not only creating myths but for them to spread like a viral epidemic. Here are some of the most common myths explained.
Myth Name: Build it and they will come
Myth Description: The belief that a website will receive large quantities of targeted traffic as soon as it goes online.
Truth: The biggest myth I still come across most days is the aptly named "build it and they will come myth". The cause of the myth is a combination of outdated information, a non realistic, over optimistic site owner or a lack of understanding of the web. Back in the old days of the internet you could "build a site and they would come", just by submitting to the main search engines of the day (to a degree). This was greatly due to the lack of web sites around at the time, meaning top positions were that much easier to secure.
Nowadays a site must be advertised just like any business. A good analogy is your site is a shop and a search engine is a high-street. The only problem is your shop is not on the high-street, so some kind of sign is required to inform passers by where you are and what you do.
Myth Name: Search Engine Submission Myths
Myth Description: The belief that a website needs to submit every page to the search engines. The belief that regular or monthly submissions will result in better search engine rankings. The belief that a website needs to keep on submitting to search engines or they will forget about the site. The belief that if a website submits to thousands of search engines its traffic levels will go through the roof.
Truth: While some of these myths used to have a bit of truth to them, nowdays search engine submission is not required at all. The myths have been mainly caused by some companies who provide submission services. This is because it's financially in their interest for people to believe the myths are true.
It does not hurt to submit to the major search engines but indexing can be achieved faster by simply getting links to a site (as long as the page where the link is on known to the search engines).
There is also no point at all submitting to thousands of search engines. There are only a handful of search engines that people actually use. Many of the other search engines have been created to obtain the submitters email address which is then added to email lists (which spammers will pay money for).
Myth Name: Meta Tag Optimization
Myth Description: The belief that search engine optimization is just about Meta tags.
Truth: Meta tags used to be very important to rankings until search engines became more complex. While some Meta tags are still important like the description and title tags which most search engines display on their result pages (so they can influence click through rates drastically). Most tags like the keyword tag are obsolete.
I believe the cause of this myth is twofold. One, because it's outdated information (to a degree) and two, because people want to believe there's a secret magic formula that only SEO's know about. That way a lack of rankings is not their fault, plus it keeps the conspiracy theorists happy.
Myth Name: Black Hat & White Hat Search Engine Optimization
Myth Description: The belief that there are two types of SEO, black hat and white hat (the old good versions evil).
Truth: Quite simple this one but almost always over looked. Any attempt to alter the search engines results and obtain more traffic is against most search engines guidelines. While there are tactics that may get you banned and others that may not or are not widely known about (yet), they are all trying to influence the results and therefore are against the guidelines.
SEO is neither black nor white, but many shades of gray. Just try to know what you're doing and more importantly the associated risks.
Myth Name: Google's PageRank (PR) is the most important aspect of a sites ability to rank
Myth Description: Self explanatory this one, the belief that PR is a God like entity we must all worship in order to obtain rankings.
Truth: It is widely believed by expert SEO's and even been stated by Google Guy (a Google employee) that the PR we see on the toolbar is out of date as soon as we get to see it. Google update PR constantly but only update the toolbar PR now and then. PR is also only one part of a complex ranking system. How big a percentage it plays in rankings, only Google knows.
One thing for sure, it does not matter how good your PR is on the toolbar, it's not going to get you anymore traffic from Yahoo or MSN (you heard it here first).
There are many more web design myths about SEO, most of which can be spotted if you read between the lines and think about whether it would make sense from a search engines perspective. One of the most important parts of SEO is finding a reliable source of information. If you want to learn more, a good place to start is one of the numerous SEO Forums on the web.