I think any corporation's power should be limited. Especially a corporation such as Google, even though it is one of the better entities out there and is seemingly good. Power corrupts people and it corrupts corporations as well. So it is best to reign in this sort of thing quickly.
I believe Google's power should be limited. It is difficult to avoid their services on the Internet at this point and I find that to be a problem. If anything, they are approaching the point of monopolizing a large part of the Internet. I'm not sure how we can combat this problem, but it should be addressed.
Monopolies such as Google should not be bounded by any restrictions other than the law. This is part of their freedom and choice. Whatever research or development they are doing would bring more advanced technologies to the society, and that is always beneficial. Albeit competition from other firms would balance the power of Google, however Google over the past few years has proven to be a much more competitive firm than its adversary, hence the rise of Google from a competitive firm to a monopoly, leaving other firms such as Yahoo behind. Therefore nowadays it would be extremely hard to find a suitable way to balance Google's authority over the globe.
No, Google's power should not be limited, as long as they are using their power legally, and not using it to help the American government spy on the American people. But if Google does the best with its email, its open office, and its google search results, by all means it should continue.
Their power should be limited by law and rules for monopolies, but other than that why should it be limited? They are a business that is innovative and has proven itself at the top of it's game. As long as they are following the law and letting users understand what they are getting into, then it's okay.