There are two important things to realize from this newly discovered information. First, it shows that Blizzard is hard at work on Wrath of the Lich King, and is already starting to include content in the patch files. We saw this same behavior in patch 2.0 with Jewelcrafting recipes. Secondly, note the rank of the inscription. Rank 3. This is a strong indicator that there will be multiple ranks of inscriptions and power increases. If Blizzard holds true to current formulas and mechanics, we can expect a mostly linear trend in the amount of power granted by the inscription.
Quite a nice little preview at WotLK content. What do you think of this glimpse at things to come?