First of all, understand that IE7 isn’t going anywhere. We’re going to have to write our markup to render and function acceptable in that browser for years to come. In fact, many of us still need to put in conditional comments and tweaks for IE6! As a result, people will still have to ensure that their pages render properly in IE7, even after IE8 comes out.

At the same time, alternative browsers have gained enough market share that they can’t be ignored. Thus, designing to Standards + IE6/IE7 allows your web pages to be accessible to nearly the entire market.

So what happens when IE8 comes out? Nothing. IE8 will treat all HTML 4.01 compliant pages like IE7 pages. So we just apply the Standards + IE6/IE7 technique just like before and we get IE8 for free. Sure it might not render quite as well in IE8 as other non-IE browsers, but it won’t be any worse than IE7. Similarly, you can code for HTML5 and pop in a element for IE7 rendering mode and not have to worry about how the page renders in IE8. Thus, any special markup for IE8 must be cost justified, which is difficult for a new-kid-on-the-block browser that renders IE7 content just fine.

By contrast, alternate browsers have nothing to gain by implementing the new switch. By sticking with their Standards-only (with quirks mode) strategy, they force developers to write standards-compliant markup in order to effectively target them. Furthermore, they’re not in danger of loosing their current market share if they fail to support the switch, because their current user base finds their current support for web pages acceptable without an IE7-specific rendering mode.

Since web developers have to write to standards anyway to target the growing number of alternative browser users, can use inexpensive standards-based improvements (such as the new types in Web Forms 2 or CSS3 rounded borders) with ease. So the standards-based content moves forward while stagnant IE7 fallback markup is fed to IE8 users via conditional comments.

But won’t new pages developed for IE8 save the day? Not really. If you really wanted to go Microsoft-proprietary, you could use Silverlight instead, which works on pretty much any Mac or Windows browser (and some Linux systems when Moonlight is finished).

Furthermore, people developing web pages that they test only on IE8+ will create pages that are gradually more standards compliant as each rendering mode improves upon the previous one. Thus, the extent of browser lock-in diminishes with each successive version of IE, and competitors will be easily be able to handle the new content generated for those new versions of IE.

Then there’s “IE=Edge”. This feature is nice in that it allows you to target the most standards-compliant rendering mode, but until Internet Explorer renders standards-compliant pages as well as its competition, developers will still be forced to specially target each rendering mode. So if there’s still at least 10% of users on IE7 when IE9 comes out, do you really think web developers are going to target two extra rendering modes on top of the standards-compliant browsers they have to target to get the other 15% to 20% of the market right now that use something other than IE?

So, Microsoft is in a trap of it’s own making. There’s little benefit in developing for the new IE8 rendering mode, each successive rendering mode is more compatible with the rendering of competitor’s browsers, and their most effective tool for vendor lock-in is a cross-browser plug-in. Microsoft has lost the browser war; they just don’t know it yet.