incrediBILL - 11:05 pm on Jul 18, 2010 (gmt 0)
Google's webmaster guidelines [google.com] are very clear:
Hiding text or links in your content can cause your site to be perceived as untrustworthy since it presents information to search engines differently than to visitors. Text (such as excessive keywords) can be hidden in several ways, including:
* Using white text on a white background
* Including text behind an image
* Using CSS to hide text
* Setting the font size to 0
Heed the advice of Planet Patrol's song and "Play At Your Own Risk" but don't get mad when you get penalized because it was posted "DO NO DO THIS" in plain B&W text.