IE8 - in actionTR: Do you feel that providing for legacy users forces Microsoft to make a trade-off?

JC: There are trade-offs, there's no doubt about this and its similar on the Windows side. I still have people using Windows 90-something. The reality is that there are good reasons and less good reasons to stay with legacy technology, but being Microsoft and being an industry leader that becomes a serious commitment.

The companies that are not prepared to make that commitment would struggle to get to the industry leader position.

To create stranded customers would be a terrible decision. There are businesses that are still using IE6 and have developed unique applications for it. They've made significant investments in that platform so we need to create a bridge so that they can still benefit from that investment they've made as well as a bridge to the future.

So that's a key differentiator for us.

And it's not just about functionality but also on security, on bringing updates and patches to continue to maintain those older versions so that people who are using them can still do so securely.

TR: At what point do you hit the kill switch for older versions? Would it be sensible to have a clear date that support will end, so that people developing for specific browsers know when they will no longer be suitable?

JC: If you were to use the Windows XP example, we developed that in 2001 and go into extended support in April of this year and there's another five years to go after that.

I do think we do work closely with businesses to get them to update and do work hard to move people to the latest versions. We have great support technology; things like Windows Update, so people are being brought the latest in a very systematic process so that people can have confidence.