As far as I know, there is no provision that exempts information in digital form from the protections of the Constitution.
And guess which big data sucking company was all to happy to turnover the gmails of AP reporters to the Justice Department?
Hint: That CISPA loving search monolith that wants us all to store everything in it's digital cloud and wear it's stupid fucking camera glasses everywhere it's stupid fucking robot chauffeurs drive us.
Hi-tech sleuthing for rounding up leakers...how innovative!