Now, Google has this clever new feature Gina pointed out on TWiG, which I think is really slick.
If you're like me, you add many web posts to your feed and sort them by category. This sort is best handled with folders. Well now there's this nifty little feature called "sort by magic" which is an option under the "Folder Settings" pull down.
What it does is sort to the top of the list items that it thinks you will be most interested in based on your browsing habits. If you've shared, emailed, starred or "liked" certain types of posts in the past, it will elevate similar items to the top of your list. It works best if you have a lot of unread items as it will not show any regard for read vs unread items.
One more way in which Google knows even more about our browsing habits and interests. Ostensibly so they can sell you another ad.