Matt Cutts: Gadgets, Google, and SEO » Hidden links

Most people understand hidden text is something like white text on a white background, and know to steer clear of it. Let me show you an example of a hidden link. Normally a hidden link could be in several forms:
- hidden text that also happens to be hyperlinked, e.g. white text on a white background, and the text is a link
- using CSS to make hyperlinks that are tiny, like 1 pixel high text
- hiding links in something like the period in the middle of a paragraph of text

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Someone went to a fair amount of trouble to hide the porn site link. The status bar gets set to empty using the onMouseOver action, so when you mouse over the link, you don’t see that it goes anywhere. And the style of the link is set so that the cursor doesn’t change when you mouse over the link as well. In my opinion, this is a good example of a link that crosses over into deceptiveness and violates our quality guidelines.

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