Web site promotion software tools
Many webmasters overlook a very important aspect of web site promotion: the validity of the HTML code.
What is valid HTML code?
Most web pages are written in HTML. As for every language, HTML has its own grammar, vocabulary and syntax, and every document written in HTML is supposed to follow these rules.
Like any language, HTML is constantly changing. As HTML has become a relative complex language, it's very easy to make mistakes. HTML code that does not follow the official rules is called invalid HTML code.