I'm Canadian so I don't really understand how these "PAC" things works. The article says that by law Facebook the corporation is not allowed to give donations to politicians but they're allowed to collect money from their employees and forward it along with a wink, wink, nudge, nudge Facebook would like this?

As an employee, why would you go for this? If you prefer a republican candidate and gave money to Facebook to give out on your behalf can they just go ahead and give it to the opposition of your preferred candidate?

I imagine this was initially done by labor unions in the past and now corporations have co-opted this loophole but still, this all seems very strange to me.

Also, does Facebook have a responsibility to track who's giving what? Because if they have international hires on staff, surely only citizens of the US can donate?