Software is set to undergo major changes in the way it is sold, with a number of different business models about to become mainstream. 

According to Microsoft CEO Steve Ballmer, "the evolution of the software business to being a business of software and service is fundamental. And we are investing in that as if it is fundamental.
"We will evolve our business models from transactions to in some cases subscription, in some cases hosting, in some cases advertising, in some cases we'll continue on the transaction model, but our business models will evolve with the evolution of our business to have much more of a service component."
Ballmer adds that while there is an element of threat to changing the software model, he views it as a huge opportunity for companies like Microsoft.
"In some senses the more we can have an ongoing, continuous relationship with our customers, be those large account customers or consumers or small businesses, the more we can have an ongoing relationship, the more opportunity we have to add value.
"So I think of this as fundamentally a very, very good thing, but nonetheless it brings with it a world with new competitors and new challenges."