Verification builds:
1.2.0.2 Retail

Summary:
Armour stands are supposed to be able to change their pose according to the strength of redstone power they are receiving. This feature doesn't seem to be working.

Steps to Reproduce:

1. Place an armor stand
2. Power a line of redstone into it

Observed Results:
The stand doesn't change it's pose

Expected Results:
It should react, and change it's pose based on the strength of the signal it receives.

Screenshots/Videos attached: Yes

Notes:
References:
Tweet describing the intended behaviour:

You can also choose poses using incoming redstone power Pretty cool for automation!

Also notice the How To Play section describes the intended behaviour: