I don't think google is worried about people not visiting the homepage. And ElZagna is right that messing around with the logo is not something new. Google makes its money on advertisements that show up *after* you search. I think they're more than happy to have the search engine practically built into the browsers these days. You can't ask for better visibility than that.

I'm not paranoid, and probably not searching anything unusual, but I choose to opt out of the data mining Google does, and since Bush allowed Big Brother to snoop on our searching, I'm opting out of that too. It's really gotten too silly out there. Example. I read an article about Iran here, search for some maps of where exactly the Iranian nuclear facilities are, then grab a link to “Dirty Bomb” from NPR, and then I think about how that could fit someone's idea of a person who's just a little too interested in nuclear terrorism.

Even so I often go straight to Google when doing significant searching.

Let me add that Google has been playing with its logo from the beginning in direct contradiction to the traditional brand marketing mindset.