Amazon has been threatened with a repeat of the boycott that it suffered in 2000 if it pursues any other company for a licence of the cookie patent that it was awarded on Tuesday.
"If Amazon begins attacking anyone over this, we will relaunch the boycott of Amazon," Stallman wrote in an email to ZDNet.
Stallman last organised a boycott of Amazon in 2000, when the online retailer launched an unsuccessful infringement lawsuit against rival bookseller Barns & Noble over its infamous one-click patent.
At the time, Stallman wrote an open letter to publisher Tim O'Reilly explaining the reasons for the boycott. The letter, which was prompted by a statement from Amazon chief executive Jeff Bezos calling for software patents to last no more then five years, said that such a law was still far from imminent, and that Amazon was still responsible for its actions.
"We singled out Amazon for a boycott, among the thousands of companies that have obtained software patents," said Stallman, "because Amazon is among the few that have gone so far as to actually sue someone. That makes them an egregious offender. Most software-patent holders say they have software patents 'for defensive purposes', to press for cross-licensing in case they are threatened with patent lawsuits. Since this is a real strategy for self-defence, many of these patent holders could mean what they say. But this excuse is not available for Amazon, because they fired the first shot."
Although that boycott did little to dent Amazon's bottom line, it did raise the profile of the debate over software patents, which many feel are out of control. Amazon UK was not immediately able to comment on whether the company is planning to use the cookie patent to sue other e-commerce sites.
Cookies have been used to customise Web sites since long before Amazon filed the patent in January 2000, but there is a crucial difference, says the patent, between the "traditional" way of doing things and Amazon's idea.
The difference lies in the process that happens when a user returns to a Web site after their personal details have already been captured and stored in a cookie on their PC.
In the mundane model, says the patent, "the information contained within the cookie is used to access a back-end database to retrieve additional information about the user, such as the user's preferences or account information. This database information may then be used to customise the requested Web page."
One problem with this approach, says Amazon in its patent, is that it requires frequent accesses to the database. "For Web sites that experience many thousands of hits per day, the need to access the database can produce significant performance degradation. The performance degradation may be the result of a limited load capacity of the database system, increased network traffic between physical Web servers and the database system, or both."
In its patent filing, Amazon says it overcomes this problem by storing within cookies all of the user information needed to customise the Web pages, or at least the most frequently accessed Web pages. "This would allow accesses to back-end databases during page requests to be reduced or avoided."