Long ago it also applied to drops as well...in that a game wouldnt drop an SOJ until a manald and a nagel also existed/dropped. So by holding each in your stash you could have an SoJ drop a lot..and I do mean a lot...more than rares it seemed sometimes. The trick was once you had an SoJ it would then only drop rares. So those who didnt want to get another "useless" unique ring would keep a manald, a nagel and an SoJ in the stash to get more rares...those who wanted to horde SoJs would mule them and then continue with their main character until another dropped. All of this no longer applies to .10 though....or the patch before that either I think.