Sony's PlayStation is to challenge Microsoft's Xbox in its one undisputed area of dominance - the online world.
The PlayStation 3 will be "network ready" out of the box when it launches in November and will offer a range of services similar to Xbox Live.
Speaking to developers, he said online games would transform the industry.
Mr MacDonald, vice-president of Sony Computer Entertainment Europe's Worldwide Studios, said: "The PlayStation 3 has been designed so that the network experience is part of the PlayStation experience.
"It is easy to connect, easy to download files."
He said development studios had to re-think their strategies for games releases, arguing that the online space gave them a powerful new relationship with studios.
He said: "But the relationship will only start at the point of sale in the network-centric world. Developers have to change their whole approach."