The technological base of (the content of) the network determines the cultural superstructure of (the content of) net art.
This is why net.art 1.0 was (allegedly) about producing 404 pages and net.art 2.0 is (allegedly) about consuming the media and relationships that are out there: it's what the network afforded at the time.
Social relations and non-network media are network content in Web 2.0. There is no difference between hacking up a 404 in 1994 and ironically posting links to existing media with your friends on a group blog in 2006. Both exist in the same relation to the network and to society.