Affiliate system allow affiliates to earn a profit through purchases/subscription made by their clients. It encourages your members to share and introduce your website to others. It is a perfect tool to track referrals to your website.
E-Library/Books Plugin provide an opportunity to create a real library on your website. You and your members can "Create a New Book", organize them into various categories which will auto Share to News Feed Page. Also, Members can Read Books on your website or Save Offline (Download)
Location Filter has Profile Map Widget that you can add to your Members profile page to show, on the Google map, the location of the member. It will also allow you to see Route from your location to members location on the Google Map. Location Filter Allow members to search other Members within specified radius to their current location (e.g you can set within 20km).