Great question!  We recently changed the community Welcome page to make it more engaging and better promote blog posts and the "featured" discussions work a little differently.  When you feature a discussion the "Newest" section on the right side will be replaced by "Featured" discussions so you can decide what is displayed there.  You can feature a discussion with the star icon that is under the profile picture of the person who started the discussion.  You'll only see this icon in your own community.