“On December 24, 1994, Compuserve and Unisys tried to give themselves a Christmas gift and make the Internet pay for it.”
GIF was free until Unisys remembered it held the LZW patent. Then owners of non-commercial and private web sites got the “opportunity” to buy a license for $5,000 or $7,500. Free software dropped the format and Gzip came out of the same fight. A dying mainframe company found a patent and sent the whole web an invoice.