"News Bins" are containers that permanently store items you copy into them. News bins themselves are no subscriptions, get never updated and produce no items of their own. You only can copy items into them and remove items from them.
As they store the items permanently and do never drop them, even when you remove the original feed, news bins are optimal for categorizing and saving items. Just given the news bin a speaking name and use as a category container!
To create a new empty news bin select "New News Bin" from the feed list context menu or the "Subscriptions" menu. Ensure to give it a good name, click "Ok" and the news bin should be created in the feed list.
To copy an item into a news bin select an item and select "Copy to News Bin" from the item context menu.
Select the news bin and select the item you want to remove. Then select "Delete" either from the "Item" menu or from the item list context menu.