Matthew Magain suggests that PHP developers are most likely to adopt Rails. I don’t see any specific reason, apart from the fact that PHP developers are already used to the open source environment. Otherwise PHP has more off-the-shelf functionalities/packages available. To enjoy benefits of the Rails design there is already an excellent PHP alternative – CakePHP. I think they might be more open to learn the programming language Ruby though, which provides a fresh alternative with the philosophy of lesscode.