Merge pull request #4397 from segmentio/ashton-huxtable-patch-1

Add info about source options for subdomains

Author: stayseesong

src/connections/sources/catalog/libraries/website/javascript/index.md

@@ -756,9 +756,11 @@ Segment offers video player 'plugins' so you can quickly collect video events us
 
 ## Cross-subdomain analytics
 
-Analytics.js tracks across subdomains out of the box; all Segment destinations fully support this feature.
+Analytics.js tracks across subdomains out of the box. All Segment destinations fully support this feature.
 
-To track activity on your subdomains, include the Segment Analytics.js snippet on each subdomain. Segment sets users' `anonymousId` on the top-level domain, so users are tracked across any subdomains.
+To track activity on your subdomains, include the Segment Analytics.js snippet on each subdomain. Segment sets users' `anonymousId` on the top-level domain, so that users are tracked across any subdomain.
+
+Because Segment tracks across subdomains, you can either use the same Segment source, or use separate sources for each subdomain. What you decide depends on your team's goals for tracking each subdomain. 
 
 ## UTM Tracking