One of the ways to organize your contact database in Relenta is to use Contact Groups. They are are hierarchically organized into Categories and can be managed in Settings > Contact Groups.
In the left vertical Groups tab, you can collapse categories for compact view, and drag-and-drop to reorder the display sequence. This is done individually by every user, allowing everybody to create their own sorting order.
Email marketing features in Relenta work on a group level. You can send an email newsletter or email autoresponder sequence to any group of contacts.