Of course, it's probably far easier just to break into the originating endpoint client, and government hackers are already very capable of that.
Reason No. 5: People make mistakes
A lot of people who think they've hidden themselves stumble sooner or later. Antimalware hunters have a pretty successful record of tracking malware writers back to their personal accounts, usually due to one small mistake that links account A to account Z. One friend, Brian Krebs, tells entertaining stories about following trails between private and public accounts. He's talking about guys who are making millions of dollars stealing money online and have every incentive to keep their private lives private.
Reason No. 6: You don't really know who you're talking to
Lastly, the person you're communicating with may already have been caught in some cyber sting and is using you as his ticket to a lesser sentence. A perfect example is Hector Monsegur, an Anonymous leader who lured several high-profile members to capture and incarceration. Monsegur not only helped the FBI nail Anonymous members, but he actively encouraged them to do more criminal hacking. Heck, one of the best arguments against guaranteed anonymity is how many of the Anonymous group's members have been arrested since law enforcement authorities started concentrating on them. You could build a new Wikipedia entry on it. At least half of them fell because of the reasons I've listed on this page.
If you want anonymity, that's great. Just don't think that you'll have guaranteed anonymity. Because you won't. My advice: If you need absolute anonymity, don't use the Internet. You're far better off using just about any other method of communication.
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