This Simple Feed Viewer will display RSS or Atom feeds in your Trello cards. The feeds are fetched on-demand, so they are always updated. You can add feeds to a card by just adding their URLs as attachments.
Badges are shown on the cards notifying you how many feeds are attached to each card and how many feeds were updated since the last time you viewed then. So you won't ever get lost in a sea of news.
If you have an URL that is a feed, but doesn't have "feed" or "RSS" in it, just give the attachment a name that contains one of these words so the Power-Up can know what to do.