My software never forgets what I tell it. I've accumulated over a dozen dozen passwords, door codes, and PINs over the years, but while I don't use most of those 150-some services these days they're still clogging my password manager. My address book has hundreds of entries spanning almost a decade, but while all of those people are memorable, most I haven't thought about for years. My music player is full of music that I bought years ago but no longer enjoy or don't prefer to hear outside of the holiday season.
What I want is software that can archive information I don't need or want, but can retrieve it when necessary. Most of the birthdays on my calendar are for people in my address book that I lost contact with long ago. I haven't logged into the Seventeen or Bust website for years, but I might again one day (despite the lecherous name, it's actually a math thing I ran into while taking courses on Chaos Theory). I don't want Christmas music to pop up when my music player's set to random, but that doesn't mean I want to delete it. Archiving and later retrieving forgotten content is a common concept in email clients, but for some reason its musical equivalent is embodied only by "Best of the Decade" compilations from Readers Digest.
I hope one day I have software that meets this need. I'm also waiting anxiously for the "Best of the 90's" three disc set: I haven't listened to that one Tal Bachman song in about a minute!