The patent application, filed in May 2002, but made public on Thursday, would cover a system that allows people to preorder a used item from an unspecified seller when that item isn't yet offered by anyone else on the site.
The application's timing is interesting because it was filed just two weeks after Amazonfrom The Authors Guild, which criticized the company's then year-old system for selling used books, saying it would hurt publishing industry profits. The guild, which is the largest organization representing published authors, asked its members to remove links to Amazon's site.
Amazon CEO Jeff Bezos responded to the criticism byto members of the guild, urging them to support his company's sale of used books because, among other things, it would expand the market for authors.
Amazon spokesman Bill Curry wouldn't elaborate on the patent application except to say that it was unrelated to the spat with the publishers. "They're separate events," Curry said.
Like many companies, Amazon has been building a patent portfolio to cover products and services it's poured money into developing and from which it expects to profit. The e-commerce powerhouse has tried to cash in on a slew of patents over the years, in areas ranging from itsto its affiliate and donation programs.
Some of those actions have prompted calls for a boycott among open-source advocates, who protest that some patents slow innovation by curtailing the adoption of certain obvious Web features.