Following are the 9 Biggest SEO Mistakes which Web Designers & Web Developers should avoid.Splash PageI’ve seen this mistake many times where people put up just a big banner image and a link “Click here to enter” on their homepage. The worst case — the “enter” link is embedded in the Flash object, which makes it impossible for the spiders to follow the link.This is fine if you don’t care about what a search engine knows about your site; otherwise, you’re making a BIG mistake. Your homepage is probably your website’s highest ranking page and gets crawled frequently by web spiders. Your internal pages will not appear in the search engine index without the proper linking structure to internal pages for the spider to follow.Your homepage should include (at minimum) target keywords and links to important pages.Non-spiderable Flash MenusMany designers make this mistake by using Flash menus such as those fade-in and animated menus. They might look cool to you but they can’t be seen by the search engines; and thus the links in the Flash menu will not be followed.Image and Flash ContentWeb spiders are like a text-based browser, they can’t read the text embedded in the graphic image or Flash. Most designers make this mistake by embedding the important content (such as target keywords) in Flash and image.Overuse of AjaxA lot of developers are trying to impress their visitor by implementing massive Ajax features (particularly for navigation purposes), but did you know that it is a big SEO mistake? Because, ajax content is loaded dynamically, so it is not spiderable or indexable by search engines.Another disadvantage of Ajax — since the address URL doesn’t reload, your visitor can not send the current page to their friends.Versioning of Theme DesignFor some reason, some designers love to version their theme design into sub level folders (i.e. domain.com/v2, v3, v4) and redirect to the new folder. Constantly changing the main root location may cause you to lose backlink counts and ranking.“Click Here” Link Anchor TextYou probably see this a lot where people use “Click here” or “Learn more” as the linking text. This is great if you want to be ranked high for “Click Here”. But, if you want to tell the search engine that your page is important for a topic, than use, that topic/keyword in your link anchor text. It’s much more descriptive (and relevant) to say “learn more about {keyword topic}”Warning: Don’t use the EXACT same anchor text everywhere on your website. This can sometimes be seen as search engine spam too.Common Title Tag MistakesSame or similar title text:Every page on your site should have a unique