You might have noticed the Memberships tab on a user’s My Site (http://mysite/_layouts/MyMemerships.aspx?accountname=domain%5Cusername), and wondered what exactly is listed there:

What you see is Distribution Lists that the user is member of. You also see Sharepoint Sites that the user is a member of (=the user is member of the “Member” group for the site. All sites on the levels below will also show if the “Member” group exists in these sites).
The “Sites” memberships depends on Search. If you cannot see any sites memberships, try running a full crawl.
The Distribution Lists memberships depends on the User Profile and User Profile Synchronization. A common issue can be that you import user profiles from a selected OU in AD as per best practise. If, however, your groups are placed in another OU at the same level or levels above, Sharepoint will not now about these membership. So, if you can’t see any Distribution Lists on the Memberships page, change the Synchronization Connection for the User Profile Service Application to include the OU where you have your groups and run an import.
You might also notice that Security Group Memberships are not shown. They are, however, displayed in the Newsfeed:

