On: Twitter Security Collapses; Obama, Fox and Britney Accounts Hacked

More users -> more attackers -> more holes found.

Attackers can only find holes that are there to begin with.

There are always holes.

Some architectures are more resistant than others. I suppose you could break into some air gapped military computers -- if you had a nuke.

why are we even discussing this?

Or someone on your payroll on the inside.

Well that's universal. You can't exactly protect against someone who's also supposed to hold the keys to the system. Its more a feature than a bug.