Linode is a Linux company, but it's also a company founded in 2002-3. Back then, there weren't many great options for web programming and ColdFusion would have made a degree of sense (PHP 4.0 was released in 2000, and Ruby on Rails 1.0 didn't appear until 2004; Django was released in 2005). A modern, reasonably-secure web stack in those days really did mean "PHP with register_globals=Off". (Facebook and YouTube were both created later, and in PHP).
It's a bit surprising that they haven't moved away from CF, but this is a good example of how hard it can be to transition away from legacy technologies. It's also not clear that security would have been improved by adopting, say, Rails, given that there has been no shortage in security issues there either.
It's a bit surprising that they haven't moved away from CF, but this is a good example of how hard it can be to transition away from legacy technologies. It's also not clear that security would have been improved by adopting, say, Rails, given that there has been no shortage in security issues there either.