what is a "Shrub" and why should I be drinking it?

In this context, the word "shrub" comes from the Arabic word "sharāb" meaning "to drink". Historically, vinegar was used (instead of citrus) in colonial America as a way to preserve fruit with sugar prior to advent of refrigeration.

In our case Organic Apple Cider Vinegar with the "mother" (but not all shrubs are made this way) is the base for everything we make. To this, we add whole, fresh fruit (no juices, no concentrates, no extracts, no oils), organic cane sugar and herbs and spices which allow us to achieve the perfect balance of sweet, savory, tangy and an almost umami complexity. 

For us, we started making shrubs when my wife was pregnant with our first child as a way to provide her with a healthier, more interesting, non-alcoholic alternative to juices and sodas using clean, healthy ingredients that even our 5-year-old can understand. That said, shrubs are incredibly versatile and can be used for making craft cocktails and even to incorporate into your cooking.