The main Prospect List was previously only filterable by one date type: Last Activity Date. You can now also filter and sort by Created Date and Updated Date. These two new filters make it very easy to see who was created in a given timeframe or which records were modified. Similar to the way all filters work, you can cut down the database to the prospects you want and export them, create a list out of them, or tag them using the icons located at the top right of the table. You will notice that when you change the date filter (for example from Last Activity to Created Date), you will see the date /time column also change to match.
This feature seems like a small one but it is hugely useful.