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Why web standards are important in web design
The importance of web standards is more then just something to say, it is the way the web should be designed. There is more then just passing an HTML or CSS validator when it comes to standards. Even so there is more to making a site pass coding standards, accessibility being the primary objective. Accessibility is usability, it isn't just about disabled it is about ensuring that your site will work from the time it is published until the end of time if it needs to. It is about carefully coding a site not just using a document out of Adobe Photoshop or throwing together an insane unaccessible website from microsoft word.
Web standards are important for maintainability
When it comes to making something work, you don't want to use duct tape where nails should be used or glue where something needs to be welded. Using the right tools for the job is part of any project, whether it be on the web or in your backyard. The solution to most problems when it comes to web is to ensure that you are adhering to web standards as best you can within any given project. This ensures for longevity of the projects life with little or no structure maintenance. When you use web standards the way they are meant to be, like safety guidelines, you are separating out presentation and structure so when it is time for a redesign you are making it as easy as possible to simply replace a stylesheet or two rather then recode an entire site. This ability may not be necessary for all sites but when you are dealing with a large project it is very difficult to go back in and change all of the HTML within the site.
Web standards are important for usability
Using web standards in your design will ensure that you are appealing to the majority of people that may visit your site. You don't just want to make your site accessible to just one browser, such as Internet Explorer or Firefox, you need to make sure that it works across as many browsers as possible. It is sometimes difficult to get it working perfectly across all browsers but you really have to make sure you are paying attention to browser usage numbers. Right now most people should be checking Firefox, Opera, IE7, IE6 (there are ways to test multiple versions of IE) and Safari. These are the most popular browsers being used. When you make your site in web standards, web compliant, you should be able to mostly get the web site to look the same across all of these browsers. When it comes to Internet Explorer though, you have to make exceptions some of the time. There are ways to target Internet Explorer using an if statement that can help you change some CSS to get your site to work right in different versions of IE. But as long as you are ensuring that your design is semantic and standards compliant then you should be able to ensure cross browser compatibility in your web projects.
Web standards are important for clients
When you are building a project for a client your business is based on making that client happy. If you aren't making your client happy then you are destroying your business. That client is going to talk about their experience with you to other potential clients and if your short term or long term relationship had issues they are going to talk about it. In the short term as long as you get their project completed in a timely manner in an aesthetically pleasing manner you are going to make them happy. The long term problems are where you are mostly going to see clients potentially unhappy. Once your client discovers that their site doesn't work in a new browser or even an older browser they are going to be upset with you. They are going to think that you never did their site right because it is broken and you didn't tell them. Ensuring that you test your web design projects on as many browsers as possible and adhere to web standards is the best way to ensure long term happiness with your client's web sites. You will be especially happy when it comes time to redesign or modify their site and you used standards. The better effort that was put into the site will make your future work with that clients web site all the more easier. If you just slapped it together any slight change is going to be a headache and more work then necessary. A lot of the benefits of using web standards on clients sites is ensuring that you have to do less work to make new things work on client sites.
Web standards are about quality design work
It is more then just going to the trouble of making your site standards compliant, it is about doing quality work within your web designs. Most of us are in this field because we enjoy what we do, when you enjoy doing something it is best to do it the right way to push towards advances in the field. Quality is paramount in an industry filled with so-called experts exporting directly from photoshop and publishing.
My thanks go to Dustin for this article which explains well why web standards are important for everyone, designers, developers, clients and most importantly users