From 12/16 hotfixes: Bonuses from Embrace of the Shale Spider and Blessing of Forgotten Kings can no longer stack.
I was just wondering since Ensidia used the extra 5% stats to kill a few bosses. You can see the buff quite clearly at the bottom right of the screen in their Al'akir video (yes they also had kings).
The icon can be found on WoWhead under Embrace of the Shale Spider.
The same shale spider ironically named Exploit is present in both of their 10 man heroic kills from yesterday. Not to start a war, but what is this considered?