If it were still around, the Library of Alexandria might be on that list... and in a way, isn't Wikipedia the modern day equivalent? Even so, I can't wrap my head around software and data that's a handful of years old being considered "world heritage".
The Alexandria Library came to my mind as well. Currently, the preservation of digital cultural artifacts is haphazard and has unreliable funding. Yet items like the wayback machine are irreplaceable.
[not arguing that it was worthy of World Heritage protection] but the closure of GeoCities removed access to some 30 million web pages. [http://geocities.yahoo.com/index.php]
Digital preservation does indeed more funding/attention though. One example I've always found fascinating is the inadvertent digital preservation through piracy. There's plenty of garage bands, old games whose studios have closed, and more obscure movies that are now widely available thanks to people sharing and downloading. A lot of this stuff wouldn't really even be commercially or legally viable to sell, but piracy has made it widely available. </tangent>
