There are many contrasting opinions on what Justin Bieber’s AIM (AOL Instant Messenger name) is but in reality it is extremely unlikely to find an account that is actually monitored by Justin Bieber himself and those that are not fake are often monitored by his Public Relations and Management team.
There are dozens, if not hundreds and thousands, of various AOL Instant Messenger accounts out there (on the internet and in various forums) and it is extremely difficult to ascertain whether any of these belong to Justin Bieber himself and the truth, probably none of them do. A pop star of that magnitude has a small army of people around him, including Public Relations, Management and Record Company personnel who are tasked with protecting his safety and one aspect of this is protecting him from both real and physical stalking which could result from any leak of personal information about any of his internet accounts.
Twitter is the exception to this rule as it is a unique promotional tool, however many of the most famous celebrities still have employees who monitor even that medium for them. Also, if Justin’s AOL Instant Messenger name was freely available, it is totally unfeasible for him to answer all the messages he would get - he is the second most followed person on Twitter, with over ten million followers.
There is a serious note to this however, in that teenage fans should avoid believing any of the screen names posted are real as they could be opening themselves up to communicate with dangerous or undesirable people posing as what they know is a popular teen icon. People wishing to communicate with pop stars and celebrities in general should do so through official channels, such as Twitter or official fan sites, for the safety of all parties involved.