IE6's entrenched position came from the fact that (a) it was the latest version of Internet Explorer for a _huge_ amount of time and (b) its status as the IE dead end for Win2k and below.

When IE7 came out, any company that still had any Win2k machines had to keep designing with IE6 in mind if they wanted their new apps to work on all their computers. (I'm making the assumption that if they were relying on IE previously, they couldn't just switch to Firefox or something).

Now, IE8 I think most people can accept is going to end up in IE6's current place. It's the IE dead end for XP, a hugely popular OS. But IE7? None of those companies that don't upgrade upgraded to IE7. Home users that upgrade will also have installed the IE8 upgrade. So you're left with what? Unpatched Vista installations. These are much rarer than unpatched XP installations simply because Vista had a shorter lifespan, and Windows Vista to 7 is sufficiently undramatic an upgrade for the types of people who would take years to go from XP to Vista.

So so far we have:

- IE6 will drag on as long as XP does.
- IE7 won't last particularly long. While it's popular now,
earlier Vista computers will be replaced in the close
future (2-3 years), causing it to lose market share to IE8.
- IE8 will have a long lifespan, although probably not as long as IE6.

IE9? IE9 has never been shipped by default with any version of Windows. That means anyone who installed it did decide to upgrade. These users will likely upgrade away, meaning in the future, IE9 will be even more of a non-issue than IE7.

IE10 will likely also go the way of IE7. While it will be installed by default on Windows 8, the amount of dramatic changes in W8 will scare off many of the companies that are slow to upgrade.

So in 5 years time, what versions of IE will realistically you need to support?

- IE6 (maybe - probably, hopefully, enterprise only at this stage)
- IE8
- IE10 (enterprise will never use it because Win8 is scary and different to them
so for home users only)
- IElatest-1 So IE13 or something?
- IElatest IE14 or something.

Needing to support IE6 and IE10 will likely be mutually exclusive, so that's 4 versions for sites targeted at home users and 5 for sites aimed at both enterprise and home users. Still ugly, but far from 72. And all those versions will be dead in the timescale that the article is using. Insofar as IE6 will ever die, anyway.

IE6 for home users will be dead at that point. Most of those old early XP computers will be "broken" and replaced, even if "broken" is just slow and annoying. Using XP in five years will be like using Win98/Win2k. Yes, people do use them. No, they aren't a large enough group for most to worry about. I even have a small amount of hits from Netscape 6. I haven't a clue what my page looked like for them, and don't care.

In theory, if even IE is aiming for at least yearly releases from now on, no future IE will end up in the position that IE6 is in, and that IE8 will find itself in, as upgrading your browser frequently becomes a fact of life. The compatibility modes will be much less important too, as the shorter lived the browser, the less likely that the compatibility mode for it will ever be used.

(Sidenote: Sorry for the kludgy lists. HN has no proper formatting for them, and they were causing horizontal scrollbars)