They say keep your friends close and your enemies closer. Now in the online advertising world, your competitors aren't exactly your enemies (unless you take life way too seriously and in which case you may need to do some self-work), but they are a threat to your business if you don't pay attention to what they're doing.

So in this post, I'm going to provide nine ways to spy on your competitors' ads so you can keep your strategy agile, relevant, and effective.