It’s well documented that the What’s New web part can be very helpful in showing recent information about content in a list or document library.  It’s also well documented that to be able to add this web part in SharePoint 2010, you have to activate the site feature “Group Work Lists”.  But what happens when you go to Site Actions –> Site Settings, click Manage Site Features and activate the feature, but the web part is still missing from the available web parts list? 

More than likely if this happened to you, you are on a sub-level site and not the root site in the site collection.  One clue to the issue is to go to Site Settings and look for the Web Parts gallery.  If you don’t see that gallery, go to the root site in the site collection and go to the Web Parts gallery.  Look through the list, and most likely you will not see the whatsnew.dwp web part in the list.  So what to do?

Luckily this is an easy fix.  All you have to do is activate the same site feature Group Work Lists, but do it on the root site in the site collection.  After you do this, go back into the web part gallery, and look at that:

It’s there now, so we’re in business.  Now go back to your sub-site and try to insert the What’s New web part:

So why is this?  Certain functionality are only scoped at the site collection level like templates, web parts, solutions, master pages and page layouts.  So you have to activate them on the root before they can be available on the sites in the lower hierarchy.  Pat yourself on the back for a job well done.

To learn more about this web part and how to configure it, SharePoint MVP Laura Rogers has written a nice blog post on the subject (among many others)!