Searching for "Instagram" in the Play store only brings up clones of the app. I would guess the search algorithm takes total downloads (which will be higher for existing apps, for now) into account over matching the app name.
For 1.5 days, users were unable to find us with a search for "zite" because google was silently correctly to "site". I estimate we lost between 70-90% of potential downloads during that timeframe.