KThunder makes a very valid point and software vendors are already making it harder to do used sales of software. Services like Xbox Live, PSN and Steam are all about making a sale to you - give you convience (download) to obtain but also make it where you can't ever "sale" the product used. All the software I buy via Steam is licensed to me and I can easily install it to my PC, but I can't decide to sell game I've beaten and then transfer the license to someone else. This way there is no used outlet for my game purchases.
New console games are coming with one-time use only Online codes to stop used copies getting used for multiplayer and online content usage. Top selling games on Xbox and PS3 all have large online following and this practice for the most part will make used copies scare and unresaleble.
Software is just following the same path the music and movie industry has been down a while now.
In regards to business purchase - licenses (especially volume buys) are always negotiated upfront and the companies have to comply with what they agree to.
