But as the CSS book explains, it is semantically rich markup that is important. Intelligent markup of the content helps search engines better understand how they should weight and index web pages. In other words, it is not the text or code that is important. What is important for the search engine’s interpretation is how the code structures the text. For example, blocks of text that are not contained within the tag will not be seen as paragraphs. You may have a lot of text on your web page but without tags the search engines will not see a lot of paragraphs. Therefore you may only get credit for having a single paragraph even though you have line breaks to separate the text into paragraphs. It is quite possible that your entire text content will be overlooked by a parser if none of it is contained within tags!
Another example is how headers are defined. A header should be indicated using the <h1> tag. You can use font tags or CSS to scale text so it is header size but it will not be seen as a header by the search engines. Therefore you will not get any credit for having headers in your content. Unordered lists will not be seen if you use a bullet point character to indicate list items instead of the <li> tag.
Content is frequently poorly marked up because people copy and paste text from Word documents and other sources without looking at the HTML code. Word uses a lot of inline style bloat to format text exactly as it appears in a word processing document. Copying and pasting from other sources frequently carries over a lot of <div> and <span> tags which provide a meaningless structure to the document.
Therefore it is essential to understand HTML code. You must stop relying on a visual inspection of your web page and remember to view the source. You have to know how to replace content that is formatted by inline styles, <font> tags,
<div> and <span> tags with <h1> tags that are formatted by the style sheet. You also need to understand CSS so that you can reapply formatting to the proper tags for your content.
But don’t become a tag Nazi and forbid the use of <div> tags. These are often necessary to apply the CSS. A <div> tag should not be used to create visual paragraphs. In other words, this is a matter of making proper use of the tags according to how they were originally intended to mark up the content.