A friend of mine on LiveJournal draws some interesting parallels between the intertextual relationships connecting pieces of Heian literature and the links connecting web pages:

Large amounts of Heian poetry have survived, and scholars generally know what's what when it comes to references from one poem to another. These days, given that the average person (probably even in Japan) is no longer familiar with whole of the poetic tradition Heian poets were writing in, the poems can still be read. It just requires lots of footnotes that cite the poems that the original author was referring to, and the patience to actually read the footnotes.

Some of what we've put on the internet will almost certainly survive us. But will it still be readable when all the links are long dead?