Webmasters have long wondered if Google maintains a "whitelist" that protects certain domains from penalties. As reported on SERoundtable today, Google issued a statement to clarify the question. Their answer denies anything like a "get out of jail free" card, but it explains what they call "exception lists".
Like other search engines (including Microsoft's Bing), we also use exception lists when specific algorithms inadvertently impact websites, and when we believe an exception list will significantly improve search quality. We don't keep a master list protecting certain sites from all changes to our algorithms.
The most common manual exceptions we make are for sites that get caught by SafeSearch - a tool that gives people a way to filter adult content from their results. For example, "essex.edu" was incorrectly flagged by our SafeSearch algorithms because it contains the word "sex." On the rare occasions we make manual exceptions, we go to great lengths to apply our quality standards and guidelines fairly to all websites.