Neighbors can be added if you know their Storm8 IDs. Storm8 IDs are separate from the island names that players can view publicly. As such, it is easier to add a neighbor if he/she tells you his/her Storm8 ID.
Neighbors can send you gold 
and Mystic Maps. You may also gain a small amount of experience 
or silver coins 
by visiting a neighbor's island daily. You only may gift gold to 3 of your neighbors each day, so choose wisely! In addition, each account may receive a limited amount of daily, although the exact number is unknown. If you send to someone whose limit has been reached, he/she will not get it, and you will lose one of your precious daily gifts as well.
You may request neighbors and exchange Storm8 IDs by commenting here. To keep everything in one place, please try to make all random neighbor requests on this page. If you wish to contact a specific user, you may do so on his/her wall.