According to a cite on the Pearl Jam website I can’t link to the exact page, but if you click on the Ten Club link and then the Christmas Singles link you’ll see the cite in question the Library of Congress only keeps music on vinyl because "it lasts forever and isn’t biodegradable.
Is this true, mostly true, partly true or utter poppycock.
That must be why LC has started the Digital Audio-Visual Preservation Program!
http://www.loc.gov/rr/mopic/avprot/avprhome.html
Also, according to their website, the recorded music collection consists of:
Vinyl is an analog medium, meaning that the exact sounds are recorded, not digital representations of them as constrained by sampling rates and other limitations. Vinyl’s second major advantage, especially to archivalists, is that it physically encodes the analog sound, as opposed to magnetically encoding it as tapes do.
Vinyl’s major defect is that if played regularly, the needle apparatus will wear down the material and lead to information loss. Its second major defect is that the plastic will degrade: Plastics will `ooze’ petrochemicals over time as the long-chain polymers break up. Some plastic toys from the 1960s are already showing signs of this degredation.
NPR had a report on this a while back. It claimed the Smithsonian was re-recording everything on shellac because all the other media had one or another inherent flaw an shellac had the greatest durability. Its only disadvantage was that the discs could only hold about 3 minutes of material.
Alas, the report was broadcast on April 1, 2003, and caught many people off guard, never realizing it was a great April Fool joke. I fear some have taken it as fact. Perhaps the OP has heard a version of the story with vinyl substituted for shellac.