For supporters, when you have friends added on a friends list, any moves they make are automatically updated for your headlines.
My suggestion is to make this optional, so you can only receive headlines pertaining to your league.
Additionally, you could add other options such as:
1) only having friends headlines
2) excluding all arena-related headlines
3) having a minimum (and maximum?) purchase/sell price so for example 1k players won't spam up your newsfeed making it useless
This would make the newsfeed much much more user-friendly and thus give supporters a better experience overall. Feedback appreciated!