"To use Google Wave in Internet Explorer you need to install the Google Chrome Frame browser plugin. Or, you can use one of these browsers: Google Chrome, Safari 4, Firefox 3.5. If you want to continue at your own peril, go ahead."
I'm not an Internet Explorer user and I understand that developers hate it because they have to spend a lot of time finding workarounds for IE, instead of adding new features, but this message is misleading.
"To use Google Wave in Internet Explorer you need to install the Google Chrome Frame browser plugin." That's simply not true: Google Wave works in Internet Explorer, even though there are some features that require Google Gears or work better in other browsers.
"Google Wave depends on strong JS and DOM rendering performance to provide a desktop-like experience in the browser. HTML5's offline storage and web workers will enable us to add great features without having to compromise on performance. Unfortunately, Internet Explorer, still used by the majority of the Web's users, has not kept up with such fairly recent developments in Web technology. Compared with other browsers, the JavaScript performance is many times slower and HTML5 support is still far behind. Likewise, the many different versions of IE still in use -- each with its own set of CSS quirks and layout limitations -- further complicates building rich Web applications. In the past, the Google Wave team has spent countless hours solely on improving the experience of running Google Wave in Internet Explorer. We could continue in this fashion, but using Google Chrome Frame instead lets us invest all that engineering time in more features for all our users, without leaving Internet Explorer users behind," explains Google.
Just because you can't offer the same experience in all browsers is not a reason to mislead users. You can inform users that your application runs faster in Google Chrome or certain features are only available if you install a plug-in or a more recent browser.
It's a slippery slope and I hope Google doesn't drop support for Internet Explorer just because it's a good opportunity to promote its own browser. Especially now, when even Microsoft builds applications that don't require Internet Explorer.
"Graceful degradation is an important principle in Web design. It means that, when you put in features designed to take advantage of the latest and greatest features of newer browsers, you should do it in a way that older browsers, and browsers letting users disable particular features, can "step down" to a method that still allows access to the basic content of the site, though perhaps not as snazzy in appearance," explains Dan Tobias.