I have written on several occasions about the problem of finding what you look for rather than what you should see. This is my way of describing what Eli Pariser calls the Filter Bubble (also the name of his book).
For educators, thorough online exploration is part what might be called digital literacy. Public Learning Media has introduced Glean – an interesting tool for exploring the variety of reactions to a given issue one might find online. You first identify a topic – say Obama jobs program. You then select terms that might describe different positions on the initial search phrase – say “pro” and “con”. The search tool returns hits offering these different perspectives. Pretty cool!