Mobile advertising refers to communication in which mobile phones are used as a medium to efficiently attract potential customers. Among mobile advertising applications, barcodes are becoming a very powerful mobile commerce tool. By capturing a barcode with a camera scanner, people can easily access a wealth of information online. Barcodes have thus converted hard copies of newspapers, wallpapers, and magazines into crucial platforms for mobile commerce. However, although barcodes are frequently used for embedding information in printed matter, they have unsightly overt patterns. Concealing data in visually meaningful image barcodes (such as trademarks) instead of using extra barcode areas has the advantage of increasing the added value of using conventional barcode patterns, and thus it is desirable for future mobile advertising. This paper presents a novel data-hiding method for halftone images. Data-hiding and halftoning algorithms are integrated into the method to prevent extreme bi-level quantization in the halftoning process, for printing purposes. We first applied regular ordered dithering to divide the input continuous-tone image into discrete-parameter halftone cells. The hidden data message was embedded in the halftone cells by using a screen column-shift method. A modified direct binary search (DBS) optimization framework was then used to enhance the output image quality. Simulation results demonstrated that the proposed method outperformed a state-of-the-art method in terms of image quality and data capacity.