All these existing technologies and producers to create web sites of course lead to problems. So they must be well known and avoided in order to get a good and useful web site.
Initially, the HTML language was designed as a language for structured presenting of data, but with the growing popularity of the Internet, to it improvements for controlling of the format and layout of the document were added. The browsers made by software companies were with so different functionality and behavior, so the web designers had to consider their incompatibilities and individual peculiarities. Having this in mind, now the companies are trying to keep the standards, providing compatibility. These standards are kept by an organization which aims at developing protocols, guides, etc., to insure long life and expansion of the Internet. This organization is called World Wide Web Consortium (W3C). The role of W3C is huge in the process of preserving HTML as a language for structured data as well. To compensate the removing of the formatting elements from the HTML language, the W3C created the CSS (Cascading Style Sheets). With CSS styles used to format the elements in the HTML documents are defined. 

Another important issue for the Internet sites is the search engines optimization. We all know well and use regularly the services of Google, Yahoo or other favorite search engines. They search the contents of your site like a scanner and store them into their databases. However, site pages must be appropriately prepared to serve its contents for the search robots. For example, the technologies such as Flash serve its content to search engines with great difficulty.