First North American Serial Rights
First North American serial rights are the traditional standard in publishing. When you sell these rights to your story, you are giving a magazine the right to print your work first in North America, before any other serial publication (a.k.a. magazine).
If a magazine fails to send you a contract before publishing your work, then legally, your arrangement with the magazine is understood to be for first North American serial rights. A magazine without a signed contract that transfers copyright cannot successfully claim that it owns your story outright.
When you assign first North American serial rights to a magazine, you are basically saying that the magazine can be the first to print the story, but that it will then give you back the right to publish the same exact story however, wherever, and whenever you choose. This is the best possible deal for a magazine writer to make. It means that you not only get paid for having your story published, but that can sell the story again later for additional income.
Sometimes, magazine contracts will assign a time limit to the purchase of first North American serial rights. A typical contract clause may read like this: “The first North American serial rights shall be considered exclusive until the last day of the month in which the article is published in the magazine, or until one year from the date the magazine receives the completed manuscript, whichever occurs first.”
This means the magazine has a year to publish your story, and if it fails to do so before a year passes, you can sell your story elsewhere — even if the magazine still intends to publish it. This time frame also guarantees you the right to use the story however you'd like the month after the story appears in print, even if that month comes before a year has passed.
Both of these contract stipulations are good. They set a limit on the amount of time the magazine can “sit” on its right to publish, thus guaranteeing that you will be able to re-use your work before it becomes too old and stale to sell elsewhere. These are the sorts of deals that professional magazine writers seek out.