Threadsinging

The practice of Threadsinging is a method of magical long-distance communication. It utilizes the Threads of Onora's Weave, invisible lines of magical energy which form a latticework that roughly follows the four cardinal directions.

Mechanics

Any mage of sufficient skill is able to send messages through a single Thread. A threadsinger is one such mage who is so in tune with the Weave that they are able to deliver their messages across intersecting Threads, allowing them to reach potentially any place on Mundus.
Reaching an individual through this method can be challenging and time-consuming, as Threads are fickle things. They sway as if blown by the wind, so it may take some time for the Threads to line with the message's recipient, during which the sender must constantly be channeling the spell.
Magical institutions and wizard's lairs tend to be built on locations where Threads are most likely to converge at any one time, and these convergence points are sometimes reinforced with a structure called a nexus lock. Mages often employ specialized enchantments, summoned familiars or magical automatons which may receive the message in the owner's stead. Sending messages to such places is considered a rather trivial task for a proficient threadsinger.

Dangers

Channeling a message through the Threads is a draining process, and the longer one is tapped into it, the more likely they are to attract unwated attention. Messages which linger too long in the Weave can be intercepted by other mages, or the vulnerable sender can be located through it.
This obviously puts the mage and the contents of their message at risk from malicious actors, such as spies, criminals and mage-hunters. Lesser known are the dangers which are attracted to the user of magical powers itself. Various kinds of magical creatures swim the currents of the Weave and prey on spellcasters which tap into it.