You can filter content by publishing source on the start page. There are two ways to filter:

1. You can either click the Filter button at the top of the page then select the favicon of the feed you want from the list displayed
2. You can click on any single favicon while scrolling down the list of feed entries to filter on that particular feed.

Clicking Filter at the top of the screen or selecting All from the favicon list will restore the full display of feeds.