Microsoft's mantra for IE8 basically being IE7 (or not using the new standards compliant mode) by default is "don't break the Web". It is interesting, then, that Microsoft does exactly that with the new useragent string for IE8. …
While the only change is an update of the version number, we know from experience that a lot of sites out there are hardcoded to look for specific browser versions. In other words: The change breaks the Web, and Microsoft must surely be aware of this.
If Microsoft is unwilling to "break the Web" by shipping standards mode by default, why are they willing to change the useragent string, which will also break quite a few sites? This seems to be a major contradiction. It becomes even more puzzling when you consider the fact that IE8 will basically behave like IE7 by default. So you have their shiny new browser which is IE8, but which for all intents and purposes is IE7, except if you opt in to IE8 mode.
If they are so committed to not "breaking the Web", why do they insist on identifying an engine which behaves like IE7 as IE8? Why do they make a change which will cause problems where other changes are out of the question?
One obvious response to this is that updating browser sniffing scripts to recognize IE8 should be easy, but if this is the case, then surely updating the same pages to opt out of IE8 compatibility mode would be equally easy if Microsoft chose to be standards compliant by default.
Microsoft is also concerned about outdated intranets, but it should be trivial for Microsoft to add a setting to default to IE7 mode, perhaps for specific IP ranges or only for the local network. The sysadmins could easily change this setting before pushing IE8 out onto their networks. They could even offer IE7 as a separate download/installation option. It's simply crazy of Microsoft to use outdated intranet applications as an excuse to keep the Web broken for everyone else.
It seems that Microsoft will once again break their promises about promoting and properly supporting open standards. Their actions are so clearly contradictory to their promises that it should be obvious what their priorities are.
This is why it's so important to never take Microsoft's promises at face value. This is why it's important to never stop paying attention to their actions. This is why it's important to get the Government involved to ensure that Microsoft, for once, follows through on its promises. The company is not going to do it voluntarily.