Working on the World of Raids Guild Recruitment I needed to make sure the user was really member of the guild he claimed to represent. Since there is no official API and we don't want to ask for the user login and password, we had to find an other way.
The idea is to take advantage of the official Armory. When the user logs off the game, his character profile is updated on the website. To make sure the user is who he pretends to be, we are going to ask him to make a change on his character, wait for the armory to update and verify.
Since it's a tool that can be useful to anyone, we decided to make it a standalone service with an open API. If you have a World of Warcraft website and feel the need to verify that your users are genuine, this is your chance!
It has been in activity since the launch of the recruitment tool. So far 100 conflicts have been automatically resolved thanks to this tool.
Check out WoW Genuine.com.