Some advertisers have grown their audiences organically, without paid promotion, using hashtags and by having a real, candid conversation with their prospective and returning customers. Even if you have yet to see success with Instagram ads, or if you have been continuously confused and overwhelmed with new platform roll-outs and changes, just know that totally normal. Let be clear: Instagram shows no signs of stopping -- its reach and impact will only continue to grow and deepen.
I'm not saying you have to split these out all the time, but would not it be interesting to test? As stated above, I believe Instagram will continue to roll out new ad options in coming months and Custom Audiences is a prime spot for these types of improvements. For example, I could see 'Watched an Instagram….