Last month, ReDigi, an online marketplace to legally buy and sell used digital music files, announced the launch of its technology. This week, ReDigi releases answers to the questions that everyone is asking: How is this legal and how does it work?

How ReDigi works
# First, music files offered for sale are verified for eligibility to sell.
# The ReDigi Music Agent uses a sophisticated method of analyzing many aspects of the music file to determine its base eligibility, including identifying the song’s digital thumbprint (a proprietary, patent pending, forensic analysis of key details associated with each specific file) and confirming whether the file has been properly acquired from an eligible commercial site.
# A music file determined to be “unverifiable” or “ineligible for resale” is not necessarily an illegally obtained file; it only means that the origin can’t be identified or the source does not qualify.
# The ReDigi Music Agent does not delete or remove unverifiable files on the user’s computer; it simply identifies these files and categorizes them for the sole information of the user.
# Once a file has been verified for sale, it goes through a second verification process that includes acoustic parameters
# Acceptable files are then added to the ReDigi music marketplace for re-sale and deleted from the original owner’s computer.
# The files are also removed from any synced devices.
# ReDigi manages this process for users, so even devices synced over time will be updated with tracks that have posted for sale and sold tracks will be removed.

Launching in summer 2011 ReDigi reinvigorates music collections by giving users the ability to legally sell (recycle) the songs they’re no longer listening to and to acquire other users’ recycled songs at dramatically discounted prices