So how are they going to know what forums he is on? Do you have to give your IP address when you interview? You do realize CR isnt viewable to the public right? Facebook, myspace, online resumes, etc are easy because most people are listed by their name... Forums are listed by screenname... I'm an admin here and I dont even have his full name so how is an employer going to find him?
I guess my question is what do you mean by in depth? If in depth is just checking social networking sites then plenty of companies do that to make sure the person wont turn into an HR nightmare (racist comments, etc). Do they actually ask possible candidates to give information as to where they go or do these companies just start searching based on what was given to them on the application?