Google Maps is such a useful public service that we have started to take for granted the ability to find locations this way. I've come across it on real estate websites, and many others where maps and directions are needed. I was surprised that it didn't include my local street in St. Lucia, and in fact had the wrong name where the street should be. How common are such errors in Google Maps?
Not as beautiful as Google Earth, which gives the illusion of carrying us up into the sky to zoom down again to our own particular locations.
Google Documents is also a very handy public service, allowing people to save and email documents without storing them onto a computer. Very handy for travellers, I imagine.
The privacy issues referred to in the Wikipedia article (linked from the 23 Things instructions page) are real; even on our "private" space on Google, we should not send anything confidential or money-related or potentially embarrassing...