Using Large Graphics

Using large graphics, lots of text, tons of javascript is a mistake since this will slow your website when loading, deterring customers and search engine robots alike. It is always a good idea to consider web optimization when the website is being built so that you do not have to retro fit your site with smaller graphics and less text. A fast-loading site will mean better customer retention and a greater likelihood that a search engine spider will not abandon your site.

Pop-Up Windows

Using pop-up windows generally annoy customers and do nothing to enhance your website in the search engine rankings. How many times have you been trapped by endless pop-up windows (you know the kinds of websites we're referring to here) only to abandon the site and never come back? Google has even taken steps to block sites that contain pop-up windows and the later versions of AOL have pop-up killers as a service to their customers.

Flash

Having a Flash element on your web page will generally not adversely affect search engine spidering of your pages. However, if your customers have an older browser (without a Flash plug-in) they will not be able to view your page period. The worst idea though, is have Flash front page. Search engines spiders devour text and having a Flash front page (unreadable by most spiders) will inhibit getting your website at the top of the search engines. Not only can the spiders not read you Flash page, but you have taken up all room for content-rich, keyword-dense text. It is better to have a small Flash element on your page that to devote your enter page to Flash. If you do have an artist or entertainment page where search engine rankings are not the driving force, then perhaps consider Flash. Otherwise none to less is better.

Dynamic Pages

Dynamic pages are built using code other than html. Some examples are ASP, CGI and Cold Fusion. Search engine spiders cannot devour the text on these pages so they are unable to know how to index and rank them. If you do use dynamic pages, make sure you do not use them for any of your main pages. Also, shopping cart pages that use the "?" symbol are hard to read for many of the search engines. It is recommended to keep the shopping cart pages away from your main pages so that the search engine spiders have a chance to do their jobs.

Password-Protected Pages

Since search engine spiders and robots are not magical creatures they have no way of gaining access to your password-protected pages. If you wish to have some of this content spidered, then you may want to consider adding another level of sub-pages that are password-protected or move some of your content up one level beyond the challenge-response window. Any way you cut it, your password-protect pages will not be spidered, but then again, this may be just the way you want it.

Frames

Frames used to be something that search engine spiders could not read. Today, many spiders can read text and graphics inside of frames but it is still a bad idea to build a frame-based website from an SEO perspective. Frames are individual html pages, which are put together in a way in which it appears to be one page. Some web designers use frames for navigational purposes, others to keep a standard look and feel among all pages on the website.

Even the search engine spiders that can read the frames on the page may not know how to reconcile the pages (since a page with frames can be two, three or more html pages bound together). The main frame may have the same URL as many other pages and only a subordinate frame will change from page to page. How does the search engine resolve many pages with the same URL when displaying your site in the results? Frames are also hard to impossible to read with some older browsers. Why take the chance of disenfranchising some of your customers who don't own the latest software-hardware combinations?

PDF Files

While using PDF files (Adobe Acrobat) are not one of the bigger mistakes, they can still be used mistakenly. More and more search engines can read PDF files and will display them in the search results. A visitor can open the PDF file (if the Acrobat plug-in is installed with the browser) but sometimes navigation to the rest of the site can be a problem from a PDF file. Shifting back and forth on a website from PDF to html may cause performance problems especially when the PDF file has not be properly optimized for speed on the web.

Sometimes when clicking on a PDF file it will look as if nothing is happening while the Acrobat plug-in is being activated and the PDF file is loading. Some visitors will click the back button or leave the site at this point. If you do wish to use PDF files, first make sure they are optimized and fast loading.

Javascript

Javascript can be used for pop-up boxes, surveys, disabling the right-click button and many other uses. The drawback of using javascript is that sometimes it can slow down your web page loading and functionality and it adds little in regards to the search engine optimization of your website. In fact, for some search engines, it may even dilute your web page a bit and hurt your rankings. In addition, Javascript is also unfriendly with certain older browsers so keeping it off or to a minimum on your main pages is desirable.