PGO = Profile Guided Optimization. It allows the optimizing compiler/linker to figure out for itself exactly what the critical execution path(s) of the program (the code that runs most frequently) is/are by requiring the user to execute the code with this special pgo-instrumentation of the compiled code as many times as required to cover typical use-cases, and optimize the code based around the execution paths taken. Profile guided optimization is a strictly optional step which can be used to improve program performance (potentially) more or better than the generalized optimizer (/Ox compiler option with MSVC) can.
Fuck. Posting this is undoing my moderations. Oh well.
OpenID is decent, granted it doesn't solve the whole single point of failure problem but it doesn't try to, either. It does a good job of consolidating login and user data, so the only trust a user need grant is to that of their provider.