Blizzard has confirmed that they are planning to merge low-populated servers with higher populated ones.
In a post on the official forums of World of Warcraft, Community Manager Kalvax reveals plans to connect "low-population realms with other existing realms."
Kalvax states that "this process will take place during scheduled maintenance, connecting a few realms each week, until we've connected every low-population realm in every region to a substantially larger population of players."
It appears that the realm merge would be seamless, and does not require action from the player. Once the merge is completed, once you log in, you will notice that you are now part of a broader community of players than before.
This news comes after Blizzard completed a comprehensive study of realm population and decided that it would be best to merge realms to give players on low-populated realms a broader community to play with.
Server merges are common in the MMO space, and can better the overall player experience for low-populated servers.