Many authors wonder if online paid advertising through social media or other platforms can be a wise investment when marketing and promoting a book. John Andrade, Senior Marketing Director at Nelson Books, says the key to effective paid advertising is to build authority for yourself / the author. This is more important than sales numbers because it can build credibility and ultimately, establish a following. He recommends that authors avoid running ads with only a "buy my book" call to action, and focus more on quality content.Andrade has found Amazon advertising to be a good investment because you get a clear picture of the return on your investment with the analytics. When it comes to Google advertising, it's more about discoverability over time than turning around a quick profit.