Search engine optimization (SEO) is the process of improving the volume and quality of traffic to a web site from search engines via "natural" ("organic" or "algorithmic") search results for targeted keywords. Usually, the earlier a site is presented in the search results or the higher it "ranks", the more searchers will visit that site.
SEO can also target different kinds of search, including image search, local search, and industry-specific vertical search engines.
How does design and development effect SEO?
With a well-formed W3C compliant website design, you provide your visitors and potential customers with a great experience. You also increase your chances for better website search ranking placement. Even the prettiest websites can be a complete mess within the code, making it difficult for a search engine to traverse it.
A search engine is much like your or I. It enjoys a quick loading page with blocks of easy-to-read content, links that are related to the rest of the site, and the content you would expect to see. Many developers will create a mess of script, code and style information that makes it difficult for search engines to work through, and ultimately can effect the way the website is indexed.
SEO is not a 1-time all-in-one thing
Anyone who says differently is selling something more than SEO.
The web is always changing, and new websites and new web pages are always being indexed. In order to maintain a level of success, it's important to establsh goals, ways of tracking them and making changes when needed. There are several techniques that can be used in the construction of your website alone that provide engines with all the information they need to give your website a solid foundation for search engine placement. Additional steps can then be taken to build content, inbound links and increase your position amongst your competition.
How to tell if you're looking at a well-formed web page
You can look at the "code" of this webpage by using the link below. Just hit the BACK button on your browser to return here.
You can see that there are no extraneous scripts in the code, little to no style information within the body of the document and even the code is easy to read. This is one example of how to check a website's compliance.
There are other tools available online that validate website pages against the World Wide Web Consortium (W3C) standards. This link will send the page you are viewing to validate that the HTML (web code) is compliant. This link will validate the navigation css style sheet, or this link which contains all of the graphic/color and font information that make the website look the way it does. Finally, the RSS news feed can be validated here. As you can see there are a number of different areas a developer needs to take into consideration when putting together a website. Please feel free to contact me for a free consultation on your website's compliance.