The little hobby function is why we wise technicians and hobbyists NEVER throw away a data book. I have IC, diode and transistor databooks on my shelf from the early 1970s. We don't throw those away just because the devices are no longer manufactured or because the manufacturer has published a newer edition of the book -- we keep them because some of that obsolete data is no longer available anywhere else, including on the Internet. For instance, I have several editions of the Motorola Optoelectronics databook and Motorola has sold that line to other companies. I still have the books because I have a lot of those Motorola parts in my stock, I might find some of those devices in circuits that I'm repairing or I might find a "surplus" dealer that has some of those devices.
Dean