90% of the time, if someone redesigns their logo they've either run out of ideas or are trying to distract you from failure(s).
Of course that isn't why Google have redesigned theirs, oh no, they're doing it because it's:
"...a great reflection of all the ways Google works for you across Search, Maps, Gmail, Chrome and many others. It's also a great distraction from the ways in which Google no longer works for you across Plus, Wave, Answers, Video, Reader, Notebook, Print Ads (yes, really!), Jaiku, Lively, Buzz, Glass and many other ways we've failed to diversify."
OK, I made that second sentence up. It's one of THE GREAT SECRETS OF BUSINESS that replacing a Serif typeface with a Sans Serif typeface can instantly inject oodles of creativity, drive and profit into any business.
Seriously. I've got an MBA. You can trust me on this.