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A larger competitor has been in the news because of an FTC investigation into their advertising practices.
The Small Business Administration has a nice summary of the basic requirements on their website. Mostly common sense - don't lie and make sure you can backup with facts whatever you say that your product or service will do for customers. There are more complicated requirements for certain types of products and services, so check out the SBA link.
You may also want to check out the Federal Trade Commission's guidelines. It includes guidance regarding mobile advertising and social media advertising, as well as examples of best practices and not so great practices. Very handy guide.