TEDTalk: Eli Pariser: Beware online “filter bubbles”
Eli Pariser gave a TEDTalk about the dangers of personalization with examples of Facebook and Google. Check it out at YouTube or at the TEDTalks website.
The danger being you will only stick with your preference, get only information you like and click, not a variety of information that may be important to know. Ignorance and hiding could be keywords here.