There's something exhilarating, liberating, and perhaps frightening about an identity that gives anyone the freedom to do or say anything without fear of reprisal. You could think of the title "Anonymous" as less of an identity and more of a tool that could be used by the powerless to subvert the creeping surveillance state. But that's not quite what this is. In actuality, there are authorities trying to identify and prosecute members of Anonymous or, more intriguingly, trying to infiltrate it and discredit it by engaging in activities in its name that are antithetical to its stated modus operandi. In order to outwit their "competition", members of Anonymous require free time and technical know-how: two things many young, unemployed or under-employed men happen to have in spades. It certainly helps explain the original aesthetic and ideological tendencies that marked Anonymous's original endeavors, and also helps explain its limits: why it can't be picked up by any group to do anything. Instead of a selfless Robin-Hood-type collective, we're left with a small, relatively homogeneous group that is the only group capable of using the tool well. They all have the same axes to grind, the same sense of humor, and very similar experiences: all markers of a relatively uncomplicated identity. Anonymous didn't have to be an identity, but there just aren't that many people who have the time and the skill to use it as a tool.
While one anonymous collective is good at disrupting and tearing things down, another relatively anonymous collective is good at building things up: wikipedia. As an anonymite, you can create or you can destroy, but (to return to the topic of the symposium) can you really change anything, any existing power structure in the offline world? Offline world changes - changes in policy, changes in the flow of capital - usually require actors to maintain traceable identities. But maybe the disruptions caused by Anonymous are enough to spark offline changes by people who have traceable identities - voters, investors, consumers, and workers.
Finally, to get a sense of the possibilities of anonymous social action, its worth considering two competing popular narratives that revolve around revolutionaries, justice, and open reputations. Anonymous borrowed the iconography of a graphic novel and film from the 1980's/mid-2000's: V for Vendetta, which featured the open reputation of V, a freedom fighter (or anarchist) intent on bringing down a fascist regime. The story leaves it open as to whether V was sane or not, but his actions - toppling a regime that is obviously fascist - are treated by author and audience as having a positive outcome. Conversely, in Fight Club, we see a collective like so many military or para-military revolutionists, bent on washing away any trace of individuality in order to form a stronger coalition, only to re-discover the value of individual identity when one of them is martyred. But the real identity problem in this story is with the main character, who is either a downtrodden worker drone or the lead revolutionary. Instead of sloughing off his old, ineffectual identity for his gleaming new one, he's caught between the two, a stranger to himself. It remains to be seen as to whether the lead hackers behind Anonymous are less like Bruce Wayne/Batman and more like Ed Norton's character/Tyler Durden, and whether their minions are more like the group-thinking benign terrorists of Project Mayhem and less like the triumphant masses of the Arab Spring.