I was actually expecting that somebody did some machine learning / matching over a large set of pictures and found all those images / coordinates.

Here [1] is an interesting paper regarding P2P networks and privacy --- "Exploiting P2P Communications to Invade Users’ Privacy"

[1] http://cis.poly.edu/~ross/papers/skypeIMC2011.pdf

Looks that Google detects the type of logout and doesn't ask for two-factor authentication in this case.

It does, maybe you checked the "Remember this computer for 30 days" box last time you were logging in?

I split the code in two binaries: "code" (qsort) and "code2" (std::sort()) and then I ran both under a profiler (based on intel's performance counters).

It seams that qsort simply executes an order of magnitude more instructions for the same result than std::sort. On the other hand std::sort() code, even if it's faster, it has more branch miss-predictions.

Here [1] are the results if you want to have a look.

[1] https://gist.github.com/b97a6395c9a20c3d4cea

Thanks, that is quite interesting.

I don't think that Google Cache acts as a HTTP proxy.

No, but Google Translate does.