You can favorite structures for quick access. When you click the current structure's name, the Favorite Structures section of the drop-down list displays the top 5 favorite structures ordered alphabetically by name.
Add/Remove Favorite Structures
To favorite a structure, open Manage Structures and locate the structure you want to favorite. Click the white star near the name of that structure. The star will then be shaded to indicate that the structure was added to your favorite structures list.
To remove a structure from your favorites list, simply click the star again. To view all favorited structures, open Manage Structures and click the Favorite tab.
Structure Popularity
Structure popularity is the number of users who have marked this structure as a favorite. To view the most popular structures, open Manage Structures and click the Popular tab.