When something is in-your-face, it can't be ignored, because it's so obvious or blatant. An in-your-face political campaign doesn't try to hide the fact that it's aggressive and sometimes hostile to the opposition.
A teenager looking for an in-your-face way to rebel against her conservative parents might come home one day with blue hair, a pierced nose, and a tattoo. A journalist with an in-your-face style asks blunt — or even rude — questions and refuses to accept imprecise answers. And an in-your-face marketing campaign could include obvious product placement in a popular movie, huge billboards, and loud TV commercials.