With Internet Explorer 8 development well advanced and beta 2 due in August it is important to be aware, especially if you develop or maintain any web sites, that IE8 will by default operate in a strict standards compliance mode. One consequence of this is that some (many?) existing web sites may not render correctly when viewed in IE8.
The good news is that IE8 will support an "IE7 compatibility mode". Not only will users be able to turn this on and off themselves but at the other end, web site administrators/developers will be able to "send a message" to IE8 clients telling them that they should render the site in compatibility mode. This gives the site developer a "quick fix" until they get round to changing the site to be fully standards compliant.
The detail of how to do this is covered here.
To learn more, check out the Internet Explorer Compatibility portal on MSDN.