A Private Message feature so we can talk to people on other servers

Long story short: there are people with whom I'd like to chat that I found on the boards. Unfortunately, they aren't on EUNE. I understand that Riot may not be all that interested, and you'd have to implement more features (blocking people, inbox sorting etc) and it'd probably be the best to have the PM button on the profile rather than each comment, but I'd like to be able to message people from other servers.