This can range from text that is "hidden", either as text colored similar to the background or in an invisible or left of visible div, or by redirecting users from a page that is built for search engines to one that is more human friendly.

As a general rule, a method that sends a user to a page that was different to the page the search engined ranked is Black hat. One well known example is Cloaking, the practice of serving one version of a page to search engine spiders/bots and another version to human visitors.

WebMedia or any of its associates never employ methods that would be likely, in any way, to penalise a client site in any of the search engines.