This is a pretty neat clone. But wasn't Facebook's own implementation a ripoff of Google+?

ha i have no idea possibly. Either way that is where my inspiration came from.

I think the panic occurring already over Wikipedia being down for less than an hour reflects on just how reliable the site usually is - especially for one relying exclusively on donations.

Absolutely. Forcing users to input their password each time they buy something from iTunes, or log into iCloud in the browsers, encourages simpler passwords. To have a single account in control of everything from buying a $1 song to remote-wiping a computer is madness.