3 Ways Google Could Lose Risk #2 - I'm not sure that Facebook will become bigger than Google, but maybe. I'm just not familiar with it. I thought the first comment for a 4th way could be true also. Maybe that's why Google is expanding so much, realizing that people could move on just because Google is just a fad (Risk #4).
You could be right. They are facing some likely penalties from the EU if they buy DoubleClick because they'd have a monopoly on online advertising. I don't see anyone else, except perhaps Baidu, being a threat competition-wise, as of yet.