The IE series (<IE10) is notorious in web design industry for its stubborn CSS incompatibility with modern standards that other mainstream browsers adopted long long ago.
Sticking to MS own CSS standards is not only creating headache engineering problems that often needs weird hacks to fix, but also preventing many fancy styling techniques from being applied.
Many visual effects are not able to be implemented in IE6/7/8. Period
Even Google stopped to support IE8 http://googleappsupdates.blogspot.co.uk/2012/09/supporting-modern-browsers-internet.html
What can we expect from Jetpack creators? I guess the only party we can blame is Microsoft and their lazy IE product engineers :D