I think we're focusing too much on the storage medium in this thread.
There is no storage medium that can be expected to last forever.  Even
the documents that have been preserved today are an aberration.  What
percentage of documents did not survive? As far as the storage medium
argument goes, what makes it necessary to store the information on a
portable medium?  

Hard drive space is becoming exponentially cheaper and there is no
reason that we can't store even large collections on hard drives.
Generally, every organization not run out of a basement is going to have
a server nowadays for sharing information between colleagues. If you
talk to anyone in IT, they will tell you that any server you have needs
a way to backup the data such as magnetic tape.  As long as your
information is important enough to preserve for posterity, it's
certainly important enough to backup.  When your old server is out of
date, you copy the old hard drive to the new one.  If we're talking
about the size of data that fits on a DVD, then the amount required is
pretty trivial (500GB hard disk is $150).  This solves the problem of
making sure the data stays on a currently readable medium, unless we see
the demise of the PC (which seems to be going the other way with iPhones
running OSX and refrigerators that access the Internet).  The magnetic
tape (which must be kept off-site) is your insurance policy in case of
hardware failure. This system isn't foolproof but paper has its own
issues, too.

I think the more immediate issue that has only been hit upon briefly is
the problem of file formats. How many of us use proprietary software
formats for their documents?  If you keep your documents in Word, Excel,
Access, WordPerfect, etc. then you have the problem that your files
might survive but not the data (confession - I'm guilty of using these
myself). These formats do not freely give out their file specifications
and can really only be opened correctly by the program and version they
were created in.  How many Appleworks, Dbase, old versions of Word and
WordPerfect files are orphaned out there?  Even if you kept the files on
a medium that would last forever, chances are that your Word 2000 file
will not be readable when you upgrade to Word 2015.

Josh Tuschl