I always am fond of projects to rebuild things from the past, as I can already see that systems that I had used for a long time, are already gone. We're losing much more information nowadays, as in 1900-2000 main vessel of knowledge were books and those are available more or less in libraries, but since 2000 knowledge was been published more often in forums and web apps/blogs and those are not storable due to copyright law and privacy issues. This knowledge is or will be lost in a few years.

Not speaking of old movies/series etc. Thankfully music is still available on CDs