Web standards are basically the use of correct web coding standards as laid out by the World Wide Web Consortium (W3C). Web Standards are a set of strategies and tools to build web sites that do what it is set out to do, be it a hobby site, a business site or a paid site on contract. The web standards which are of most concern to modern business are XHTML and CSS coding practices.
Web standards compliant pages get a greater visibility in web searches. The structural information present in compliant documents makes it easier for the search engines to access and evaluate the information present in those documents, and helps in accurate indexing. The use of web standards makes it easier for server-side as well as client-side software to understand the structure of your document.
Compliant code gives the opportunity of validating a page with a validation service. Validators process the documents and return you with a list of errors which makes correcting errors a lot easier, and saves a lot of time.
Accessibility is an important idea behind many web standards, especially HTML. Standards-compliant websites allow the web to be used by people with disabilities. Making your sites standards-compliant ensures that not only traditional browsers, old and new, will all be able to present sites properly, but they will work with all unusual browsers and media.
Writing web pages in accordance with the standards shortens site development time and makes the pages easier to maintain. Debugging and troubleshooting become easier, because the code follows a standard. But there is a downside to all this, it can be difficult to find a designer who will make an attractive site which is also web standards compliant. The designers need to be made aware of the benefits of using web standards, the clients need to be educated too as one of the reasons why a lot of very talented web designers do not create sites which are web standards compliant is due to the time involved and the lack of appreciation received from the client for doing so.