Search engine spiders can find it difficult to read your website if your content is hard to read. When a spider comes across a page on your website it will be able to read and understand it more accurately if your content is structured and represented in an organised manner, with no un-necessary HTML code. This is a major factor when it comes to improving your rankings in said search engine.
Believe it or not, search engine spiders actually read certain elements of your HTML code. Certain HTML code holds more weight than other tags.
The key to optimising your website is to make sure that all your code is completely readable, because if there are unnecessary text and tags in your HTML, spiders will struggle to decide whether that page is related to a particular search keyword. Improving your code structure isn't just for search engine spiders; it makes human readability easier too.
For example, this could be your website code:
Welcome to my website, we offer search engine optimisation and internet marketing
Now lets see it in XHTML code:
Welcome to my website, we offer search engine optimisation and internet marketing
Then you would simply attach a CSS with the following code:
h1 { font-family: Verdana; colour: FF0000; font-size: 5px; }
When using XHTML, declaring your main heading as an H1 tag will make sure a search engine spider knows the contained text in the H1 tag is a title. By using header tags such as H1 through to H6, SEO professionals can use these tags to rank how important certain parts of the page are.
But, everything that is good always can be abused. Certain SEO professionals can use XHTML and CSS to hide text on a page so it isn't visible to the human eye, but can be seen by spiders. This is referred to as "cloaking", a form of SEO spamming. Spamming comes under the title of black hat SEO or unethical SEO, which is an abuse of search engines and is never advised by ethical SEO companies.
