I'm not a big fan of anonymity on the Internet. At least, not in general.
Being completely (or even simply “mostly”) anonymous online tends to bring out the worst in people. Online game voice chat. Message forums. Blog comments. We've all seen it. The worst comments tend to come from someone who calls himself “NotAChance@NotReally.com” or something like that. (Note that I used the masculine pronoun - “himself” - because ladies tend to not do that sort of thing. Because ladies are, generally, better human beings than us men.)
But there are certainly some cases in which anonymity can be a good thing, even vital to the task at hand. Such as, say, in journalism. The need for anonymous whistle-blowers is pretty critical there. Without proper anonymity, sources may not be as willing to come forward with information.
With that in mind, the New Yorker has rolled out Strongbox, an open source system for accepting news tips in a secure (and anonymous) way, which is built on DeadDrop. (Side note: DeadDrop was built, at least in part, by the late Aaron Swartz.)
The way it works is pretty simple. If I want to send a big scoop to the New Yorker, I utilize this system to connect via the Tor network, which routes my connection through a global network to help conceal my identity, and then stores the information, in a secure way, with a unique “code name” assigned to that, and any future correspondence.
Basically, it makes it as difficult as possible for anyone to figure out who I was, unless I tip my hand in the message I send.
But this isn't the only open source solution to this problem. GlobaLeaks also utilizes the Tor network (I knew that thing would be handy for something) and utilizes a distribution system similar to BitTorrent.
Both systems are pretty young, but Strongbox is up and running right now for all your whistle-blowing fun.