ipfs and zeronet (and dat project) are distributed file stores (think bittorrent), some have some special browsers n top that let you build applications
freenet is a distributed, secure content network.
i2p and tor are secure overlay neworks - run on top of the existing internet to provide secure connectivity - designed to obscure where traffic is going to and from.
gnunet and cjdns are also secure overlay networks but more like point to point vpns.
> GNUnet is an overlay network, as it is initially supposed to primarily operate over the existing Internet network. However, GNUnet does not assume that this is always the case. For example, GNUnet can also operate directly over WLAN or Bluetooth to create an ad-hoc wireless mesh network, and with the GNUnet “PT/VPN” subsystems we can run TCP/IP over GNUnet. So in this configuration, GNUnet would be an underlay network, a bit like MPLS or B.A.T.M.A.N. [NAL07]. In reality, we in fact expect to see both at the same time: some peers will run over the existing Internet, while others may connect to GNUnet on Layer 2.
It'd be amazing if these projects converge on making version control, package management and any sort of information distribution (internet) into the same thing. Currently it feels like they are all working in separate corners on what they consider to be 'the abstraction that will eat the world' so to speak..