A realm stability issues has forced Blizzard to temporarily disable the Recruit-A-Friend service. It was just re-launched yesterday with several new rewards and a brand new in-game interface. Whatever hamster was in charge of turning this wheel seems to have come down with something, so don't be alarmed if you're unable to recruit anyone for the next little while. You can follow BlizzardCS on twitter for updates, and we'll update this post when we know more.
We've temporarily disabled Recruit-A-Friend to address an issue that is affecting realm stability. No ETA just yet. Updates to follow.- BlizzardCS (@BlizzardCS) November 13, 2013