Microsoft emailed me today to warn me that Internet Explorer (IE) 8 will now be in "Standards Mode" by default instead of the "Compatibility" (sometimes referred to as "Quirks") mode the older versions have run in.
This means that web developers that may have sites out there with invalid markup may run into some issues for people viewing their sites using IE 8.
This is a GOOD thing Microsoft is doing, as it will make their browser play more like the others that are in "Standards" mode by default.
The email Microsoft sent me is to inform developers that they're not left in the dark. Microsoft has offered a way to make the sites tell IE to go back into "Compatibility" mode so it will look the same as it would in IE 7 or earlier.
NOTE: This is not an excuse not to fix your markup!!! You still need to fix your sites to be compliant with standards... this will just buy you some time until you do.
Go to Microsoft's article to find out how to use this compatibility tag should you need to.
Make sure to download Internet Explorer 8 beta and see if your sites may need this tag... your site will render differently in IE7 and IE8 if you do; if they look the same, you're a good developer! :)