How many times do you have to pay for 1-Click? That's the question Victoria's Secret, Apple and PayPal are facing. The three online retailers were sued on March 14 for using one-click checkout systems on their Web sites. But instead of Amazon, which spent years trying to get some legal respect for its 1-Click ordering patent, this time the lawsuit is coming from Cordance, which claims to have its own patent on the process of buying online with a single click—and which, it says, Amazon also infringes.That's got to be galling for Apple, which made a big display of licensing 1-Click from Amazon a decade ago. But it's frustrating for all E-tailers, who thought they would only have to pay 1-Click tribute once, to Amazon. Now it looks like they may have to buy the same rights twice—unless Amazon (which isn't named in last Monday's lawsuit) can win its fight to be the only 1-Click game in town.Confused? You're not alone. Amazon and Cordance have been fighting over who gets to collect 1-Click patent royalties for years. Amazon's U.S. patent #5,960,411 dates from 1999. Cordance's U.S. patent #6,757,710 wasn't issued until 2004, but Cordance originally applied before Amazon did.In 2006, Cordance sued Amazon for infringing its patent. In 2009, a jury found (among other things) that Amazon's 1-Click does infringe several claims of Cordance's patent, but that those claims were all invalid. In February 2010, a judge decided that the jury was wrong, that Cordance's patent is valid and that Amazon is infringing it. (Amazon is currently appealing that judge's decision.)A week later, the U.S. Patent Office ended a four-year challenge by deciding that Amazon's 1-Click patent is valid, too.That brings us to the March 14 lawsuit against the three retailers, which may not be going anywhere soon. Both that case and the ruling that Amazon is appealing are in the same federal court in Delaware. Because judges don't like covering the same ground—especially in the same building—the three retailers may have to wait until Amazon finds out whether there really are two 1-Click patents.For now, as murky as all this may be, one message is clear for online retailers: There are a lot of things you can buy in one step, but it looks like the right to 1-Click buying isn't one of them.