How do you go 3 years collecting personal information and just now realize it
Do you realize how little data, 400GB is? I've got TB's in hard drives on my personal computers, and I'm not Google with tens of thousands of machines and TRILLIONS of pages indexed. Hell, they give every Gmail account 7+GB just because they have the extra hard drive space.
That being said, think about the number of hours a fleet of street view vehicles can run up in 3 years. 25 vehicles * 8 Hours a day * 250 business days a year * 3 years = 150,000 hours - and this is very conservative. 400GB / 150k Hrs = 0.7KB/s of data. I wouldn't notice if I was getting an extra 1KB/s of data, and I'm not Google. That isn't much extra comparing that they are, at the same time: Taking 8-10 pictures, recording GPS data and recording the SSID/MAC/Location information for wifi.
What this boils down to is their software captured and kept more of the wifi packets than they needed to. I do wardriving and I too have recorded packets over open Wifi connections. Guess who's fault this is? Yours! You, the end user, have an open wifi connection - your data is being sent in the CLEAR. Don't blame Google because they accidentally picked up some stray raw packets, and never did anything with them. Just hope someone else didn't pick up your packets that has ill intentions for you.
Actually it was 600gb, but you took the time to write that all out :O. Although the data's not really usable--it picked up bits as it traveled past unsecured networks.
Ya know, I thought that was the wrong number, but I figured I'd go with what the commenter had said.
And yea, it really is useless data. What could they have picked up in that short amount of time? A Credit card number? Nope, encrypted with SSL. An email? Generally sent with SSL. They probably got some random bit of porn.
Actually, I was watching the news yesterday, and apparently, anyone can see your Facebook profile (if you accessed it) on a public wifi network with a quick, legal program. So I'm sure Google must've gotten that sort of thing if the unlucky person was on Facebook as the car passed.
All in all, Google fail. Oh, and review your code. :P