The present invention relates generally to digital watermarking and steganography. In one implementation, a method includes determining a current geographic area of the cell phone; selecting a first digital watermark detector that is associated with the current geographic area, a selected first digital watermark detector being selected from a plurality of different digital watermark detectors; and controlling the cell phone to employ the selected first digital watermark detector to analyze a signal to obtain a digital watermark message there from, wherein the selected first digital watermark detector corresponds to a particular digital watermark embedder that is uniquely assigned to the geographic area.