I just finished my 2011 tax return, and I was looking for space in my file cabinet for the many file folders that make up a year's tax return for me. (It's way too much.) I cleared out the 1981 through 1991 tax returns, which take up almost a foot of space, and scanned them in. My, how the world has changed!
Many of the early tax returns were done in pen, or on a typewriter.
Schedule W (Where Both Work): that's an IRS form that has gone the way of the dinosaur, now that few women are stay-at-home moms.
The enormous amount of useless information that California's Franchise Tax Board used to require, because they had not adopted the same depreciation rules on business property as the federal government.
Some years I photocopied my tax returns duplex (to save space in the file cabinet), and now I regret that. Single sided just loads into the hopper on my HP 1536dnf MFP, and boom! Nothing else to do. The double-sided means a lot of flipping pages and hitting + in the Scan program.
Dot matrix printed accounting information.
A 5.25" floppy disk drive that I must have stored business records on.