The Media History Digital Library. Online Access to the Histories of Cinema, Broadcasting, and Recorded Sound.
We are a non-profit initiative dedicated to digitizing collections of classic media periodicals that belong in the public domain for full public access. The project is supported by owners of materials who loan them for scanning, and donors who contribute funds to cover the cost of scanning. We have currently scanned over 800,000 pages, and that number is growing. Our Collections feature Extensive Runs of several important trade papers and fan magazines.
Physically this data might exist somewhere but the challenge is making it accessible to future historians.
"The average life of a web page, as best as we can tell, is about 100 days before it is either updated or disappears.
"We are grappling with digital migration as a means of preservation, rather than analogue, paper-based preservation. The Twitter archive ratchets up this activity enormously."