IE is not a easy browser to code for; it always seems to act differently (buggily) from other browsers and it is frequently non-standard for new functionality.
However, up until now, it's default position on Windows has meant that it couldn't be ignored. I think quite a lot of corporate IT departments didn't think the browser experience of their employees was a terribly high priority and firewalls would prevent other programs being installed.
However, this flaw will have the same IT departments running to disable IE and installing Chrome or Firefox. Microsoft must move lightning fast or their share will rapidly fall to a point where the developer community breathes a long-overdue sigh of relief and stops supporting IE.
This new flaw – in a browser used by more than a quarter of people online – was discovered last weekend. Microsoft said that a cyber criminal could tempt a user on to a fake site by “phishing”, sending a link in an email or instant message, and then obtain rights to install programs, view, change or delete data or create new accounts for a network.