Mobile giveaways or contests are an effective way to grow your subscriber list (for email or mobile marketing), and to increase your brand recognition.
The main thing to consider is the legal compliance, as certain states or areas have specific rules about contests and sweepstakes, and certain areas simply don't allow them. So you want to make sure that you participants know when they are not eligible. (You want to contact your attorney regarding the details).

We've put together a quick 4 minute video on how to set up a mobile contest or a giveaway page on piJnz: