Ad supported legit P2P network Qtrax has told the New York Post it now has agreements with all four of the major record companies. EMI and Warner had already confirmed they had signed a deal with the new service, but the Post says that both SonyBMG and Universal are now also on board.
It is still not entirely clear to me how the Qtrax service works, except that music is free to access to consumers, with advertisers covering the cost. It is one of a number of advertising funded digital music services in development, and one of a number services hoping to develop a legit business model around the P2P phenomenon.
Although business models like those being developed by Qtrax are more or less untested, Brilliant Technologies are reportedly already considering floating the new service in the near future.