Any idea where they get the number 300 years? In the archival world, we're leery of such blatant marketing claims, especially since CD technology is only a few decades old.
Not as much a marketing claim as it is a MTBF analysis procedure. They run their media through advanced heat/cold/light cycles to approximate how long the media will last. There a number of vendors/technology providers out there that are working on this technology - see http://www.millenniata.com/. Electronics vendors do the same thing when creating 20 Year+ Lifetime components - Just heat it up to 85 degrees, then drop it down to -45. Repeat over and over to advance the aging process.
I've heard that the LDS church / Vatican have both been interested in the archival media, and they have a pretty good long perspective, so might be worth checking with technologists in that realm.
According to Wikipedia, the LDS Granite Mountain Vault (http://en.wikipedia.org/wiki/Granite_Mountain_(Utah)) adds 40,000 rolls of microfiche per year. Not sure how current that info is, though; the LDS church is pretty secretive with a lot of its methodology.
