In response to user feedback, we recently changed the way we process OR and AND keywords. For the unfamiliar, these keywords allow users more control over their queries. For example, if you search "foo OR baz" (no quotes), you'll see pages that contain either "foo" or "baz" (or both). Likewise, "steve jobs" AND "steve ballmer" returns pages that contain both "steve jobs" and "steve ballmer." While we've always supported this type of query, our new algorithm changes add improved relevancy to the organic results when using syntax. Not many people use or know about this feature, so please spread the knowledge to other searchers. To our current syntax users: let us know if you encounter any remaining problems with OR/AND queries via email@example.com or the community forum.
For more information on syntax, please consult the corresponding help page here .