i believe this is called a hypervirus.

I2P is a P2P darknet. on tor the network is run by volenteers (~6000 nodes) while on I2P everyone on the nerwork is a node, and their are no built in exit nodes (in i2p their called outproxies). the official I2P router has a built in torrent client as well. like torrents the more people on i2p the faster the network, while the opposite is true for tor.