A librarian here is undertaking a weeding of our CD Rom collection. She asked me about the DLI collection, and now I am asking you. If a product is available in its entirety on the FTP (and preferably a user-access system like IDLS), what are the arguments, if any, for keeping the CDs?
1) If indeed the cd-roms are available in zipped format on the FTP, you could reproduce them at will. But this would require that you be around to access the site - persons (assistants) without the password could not access it on demand, whereas a cd-rom can be pulled off a shelf.
2) A physical copy would give you access at any time (if for some reason the FTP site was down - not accounting for the Mirror site at U of A)
3) If you already have the physical copy, help save the planet by re-using instead of re-burning
4) The DLI ftp site pretty much provides the latest edition or version, but not prior ones. Even other products in which the entire product is available on the STC web site, has important differences in editions. The Health indicators database is one of the few that comes to mind as having several editions available. And then there are also products such as ICO which are not at all self-replacing.