What difference does IT make in some of the biggest companies in the world? To find out, we looked at eight top corporations with some striking similarities and differences.

The Mega Eight have complex IT organisations with budgets running into billions and more employees than most companies. So we relied on the human element to focus each picture, presenting a chief information officer's view of the challenges and triumphs that make these companies unique. But we think IT professionals will see some of the problems they are grappling with writ large in these stories.