Achieved! allows you to customize the position and scale (size) of the achievement alert frames you see when you earn an achievement and dungeon completion alert frames (new with v0.4), as well as change how long those alerts remain on the screen. This is especially useful for players who have customized their UIs in such a way that the alerts would otherwise block important elements of the interface.
Achieved! aims to be light-weight and easy-to-use. Type /achd or /achieved in-game for instructions. See the screenshot for an idea of what it's capable of doing.