Tagitis: Tagitis is the adding of many useless XHTML tags. This header, for instance, suffers from tagitis:
<h3><em>Header</em></h3>
You don't need the extra <em> tag. One line of CSS would give the same effect:
h3 {
font-style: italic;
}
You may consider the <em> tag from the semantic point of view (the <em> tag imply a certain meaning), but I think the semantic meaning of the h3 tag already cover it.
Divitis: a common problem with webdesigners, using too many nested/unnecessary divs to mark up a page. Divs are grouping elements. They are supposed to be used to group sections of the page into divisions - for example, a top division with logo and links, a sidebar, or even a footer. They are generic grouping elements with no default style - no borders, padding, margins, fonts. The only default style of a div is that it is a block-level element - which, by default, will take up the maximum width available. Divs are not to be ignored completely. Many CSS designers use extra divs to display little niceties for the site - for example, a fixed div with a background image that sits at the top of the page. The <body> tag is a container (and you can style it too, using style='margin: 0 auto') so you don't need a div with id='container'. Any time you see a div or span with an ID or Class containing the word "head" you can guarantee it should be replaced with a heading tag.
http://csscreator.com/divitis
http://www.tyssendesign.com.au/articles/faqs/what-is-divitis/
http://www.456bereastreet.com/lab/web_development_mistakes/
http://www.apaddedcell.com/div-itis-what-it-and-how-avoid-it
http://snook.ca/archives/html_and_css/its_not_divitis
http://www.bloggingpro.com/archives/2010/01/13/what-happened-to-your-content-when-buttonitis-and-tags-take-over/
Divitis: what it is, and how to cure it.
Why tables and divitis make your site inaccessible?
http://adam.kahtava.com/journal/2009/07/15/cronic-divitis-and-classitis-what-is-it/
http://www.sitekin.com/blogdetail/avoid_CSS_Classitis
Avoiding classitis
Attributitis
http://www.onyx-design.net/featured/css-diseases-divitis-classitis/
Combating Classitis with Cascades and Sequential Selectors
