Blizzard's tooltips and skill explanations are pretty retarded. Their website isn't any better, either.
Something like half of all information pertaining to this game is hidden from the players, it's ridiculous (yes, yes, I know 70% of all statistics are made up on the spot, including this one; just trying to make a point).
My bad, I guess I never looked at it before. Sure enough, all the runes give 15% movement speed for their duration (except displacement, which is 35%). Tactical advantage provide yet another 60% bonus on top of that (additive).
I'm gonna go ahead and nominate Smoke Screen for the least informative tooltip ever.