In the old days, people could make some money by charging you $5, $10, or even $29.95 for a photocopy of a schematic or old manual they had sitting in their filing cabinet. With the Internet, if many people keep several scanned images on their web sites, eventually there will be a virtual "filing cabinet" of circuits and data accessible to everyone, essentially for free.
The Technician's Filing Cabinet is a set of links to service and technical information. Also included are links to specialty sites that have more detailed information than what is here. Sites that sell information commercially are not included.
Some Technician's Filing Cabinet data resides on the One Electron web site, but most are on other sites. All information is believed to be in the public domain - either was never copyrighted or the copyright was not renewed after 28 years. Due to changes in the US copyright law, material originally copyrighted after 1964 is likely still under copyright protection, hence the preponderance of old information. However, copyrighted-protected material is welcome if permission is granted by the copyright owner.
You may notice that there are no Sam's Photofacts schematics. Until I check further on their copyright status, I am not putting links to scanned Photofacts documents.
A few people have questioned the ethics or legality of linking to other site's information. As long as the links are not deceptive, linking is OK, as explained in this article.