Shadow, I looked up how most locks were looking at the Shadow Embrace talent quick and it appears that for raids the 5% is considered useful. For 5-mans the usefulness is roughly the same but since the mobs (generally) hit softer there isn't as much need.
One notable thing is that if everyone is using a "raid spec" (be it demon, affliction, destruction or a hybrid) and specs specifically to raid, only one lock should have this talented. Only one person is needed for it to be up and it does not stack. Also, the highest "rank" always overrides any lower "ranks."
Please also note that it applies to physical damage only, not magical.
For pvp-specced locks there is usually 1 point in it to add to drains since it counts as an "affliction effect" and also gives some limited dispell protection.
Linky to more info Warlocks Den Shadow Embrace page (http://wowmb.net/forums/showthread.php?t=15476)
Yea I was looking at that as well, said only one lock needs it. I changed my spec though since I dont really raid often with my lock these days and mostly just solo and do 5 mans with her. If that ever changed id take my points out of Shadowburn and put them back where I had em.