I noticed it by coincident. I've had some absolutely game ruining lags today. It comes and goes. Then I noticed that when the interactive part of World of Warships add, the part where you can fire on the enemy ship, is running, there is some serious lag and then when the none-interactive part of it is running there is no lag whatsoever. I don't think that it is a coincidence. I watched it for quite some time.
I'll add to that I don't think it's JUST World... I see a lag in every game I tried tonight when I interact with the mouse. From dragging and dropping to clicking. And that's some serious crap when you're playing a clicking game like Clicker Heroes or Realm Grinder.
I'll give it a few hours, maybe even a day, and then send up the red flag.
My guess is still that it is an add. I activated my add-blocker and since then, no lag. I normally don't mind the adds since a few of them have lead to interesting games, but ...