i recently had this problem when deciding to buy blank DVDs my options were either +R or -R, but after much research, I believe that my conclusion was that -R was the older format meant for the early DVD writable drives current DVD writers will read & write for either format, while most of the early DVD players and DVD ROM drives up to 2004 only take the standard DVD-R which actually explains alot, now that i think about the times I was having trouble trying to burn CDs around that time as to any other differences, there isn't that much