Whenever the press covers a story about hackers, a great deal of the discussion concerns the nature of online identity, the cohesiveness of hacking groups, and the individuals that identify with these groups. This is particularly the case with discussion of hackers that consider themselves part of the hacktivist group Anonymous.

This is due, in part, to the apparently co-operative manner in which Anonymous operates, and the oft-quoted Anonymous mantra (“we are Anonymous, we are legion”) that de-emphasises the individual and promotes the idea of the “group”.

This lack of emphasis on the individual is slightly ironic given most of the news about Anonymous in the past year – including the most notable hacks of 2011 – centred on individual hackers whose identities are known.

But issues of identity and group dynamics have been brought to a head by recent stories about the unmasking by US authorities of FBI informant Hector Xavier Monsegur. Monsegur is also known online as Sabu, and is purportedly the leader of LulzSec (an offshoot of Anonymous).

According to court reports unsealed last week, Monsegur had been helping the FBI build cases against fellow hackers soon after he was arrested and released on bail back in June 2011.

Sabu’s story says a lot about what we actually know about people with whom we only interact online. In the case of Sabu, it turns out, we didn’t know very much. His online persona was very different from his real-life self.

This perhaps shouldn’t be very surprising given people generally have multiple and varied personas online – which often, if not always, differ from their real-life personas.

The psychiatrist Carl Jung described the persona as the mask that people wear to hide their true selves from society. On the internet, the effect of a persona is more pronounced because we lose other cues – such as how people talk, where they work and how they interact with others – that could potentially reveal how close the persona is to someone’s “true self”.

Much of the coverage of Sabu’s unmasking focused on the nature of his online persona. The discussion ranged from his role within Anonymous and LulzSec, to his dominating and opinionated presence on Twitter. Other commentators have even claimed he was just a second- or third-tier hacker within Anonymous, even though he was involved with most of the prominent hacking activity that took place under the Anonymous name last year.

Sabu himself gave interviews with private internet relay chat (IRC) sessions and more detailed question-and-answer sessions on Reddit.

It took the unmasking of Sabu to reveal something approaching the truth about Monsegur as a person. The New York Times featured a story describing 28-year-old Hector Monsegur as a Puerto Rican “party boy of the projects”, who cared for his sister’s two children. Monsegur was also revealed as a petty criminal and general neighbourhood nuisance, but someone who actually did care about the social issues he believed he was fighting for.

As mentioned, the unmasking of Sabu makes it clear that it’s very difficult to know the truth about someone from the persona they present online. This is especially true when that persona is being pieced together from fragments of tweets or even chat logs.

Commentary on individuals, relationships and organisational structures within Anonymous is also almost impossible. One should ultimately be wary of anyone making claims on these subjects without appropriate disclaimers.

But it’s the reactions to Sabu’s “betrayal” of his fellow hackers that’s potentially the most interesting aspect of this whole story. Other members of Anonymous were apparently left “emotionally devastated” and “shocked” by the news Monsegur was an FBI informant.

It seems strange anyone would be surprised that Sabu’s first loyalty was to himself and his family. It speaks volumes about the unrealistic view that people have of online relationships.

Our online ties are influenced by how well we know people in real life. If we don’t know the person in real life, or have met them only casually, it can be argued that our ties with them online could only ever be weak.

This is, in part, because of the principle discussed earlier – it is difficult to really know anything about people online because their personas will differ from their real-life selves. You can never be sure who you are interacting with.

This means loyalty between members of a group who only associate with each other online is, by necessity, going to be fragile. Or to put it another way, most, if not all, online social ties are weak.

The responses to Sabu’s “betrayal” are even more curious given the turning of hackers into informants is actually quite common. This phenomenon is described well in Kevin Poulsen’s book Kingpin about credit card fraudsters who regularly turned on each other to save themselves.

The story of Sabu is probably not over yet. He has gone into hiding but it seems unlikely we’ve heard the last from him. Perhaps the most prescient comment on this whole saga to date was made by Sabu himself during his Reddit Q&A:

“Stick to yourselves. If you are in a crew – keep your opsec up 24/7. Friends will try to take you down if they have to.”