clarify tags

Author: PatrickFarley

articles/cognitive-services/Custom-Vision-Service/overview.md

@@ -28,7 +28,7 @@ This documentation contains the following types of articles:
 
 ## What it does
 
-The Custom Vision service uses a machine learning algorithm to analyze images. You, the developer, submit groups of images that have and don't have the characteristics in question. You label the images yourself at the time of submission. Then the algorithm trains to this data and calculates its own accuracy by testing itself on those same images. Once you've trained the algorithm, you can test, retrain, and eventually use it in your image recognition app to [classify images](getting-started-build-a-classifier.md). You can also [export the model](export-your-model.md) itself for offline use.
+The Custom Vision service uses a machine learning algorithm to analyze images. You, the developer, submit groups of images that have and don't have the characteristics in question. You label the images yourself with your own custom labels (tags) at the time of submission. Then the algorithm trains to this data and calculates its own accuracy by testing itself on those same images. Once you've trained the algorithm, you can test, retrain, and eventually use it in your image recognition app to [classify images](getting-started-build-a-classifier.md). You can also [export the model](export-your-model.md) itself for offline use.
 
 ### Classification and object detection