Freenet is a distributed Darknet that offers a high degree of privacy and comes with a number of features from blogs and websites, to highly secure email and file sharing. What is unique about Freenet is that when you upload a file and create a blog, it is almost impossible to take down because all content is distributed among the newtork rather than hosted on a centralized server. .
Freenet is not as anonymous as tor or i2p and cannot be used to browse the regular internet (or clearnet) but it has a number of great features that, unfortunately, anarchists or the left have yet to take advantage of it.
Cons: like all distributed darknets, Freenet has been used for illegal purposes, namely illegal pornography. You should read up on the legal risks of using freenet before using it. Freenet also requires that you give up a chunk of your hardrive space (from 1 to 20 gb) in order to use it. That portion of your hardrive will be used to host encrypted peices of the network as a whole. The freenet project advices that you keep freenet running at all times.