If, like me, every time you cook spaghetti, while the water's boiling you frantically search the web for a transcript of Season 1, episode 10 of Good Eats (Pantry Raid I—Use Your Noodle) to remember whether Alton Brown says to use a teaspoon of salt or tablespoon of salt per quart of water:
It's a teaspoon. One teaspoon of salt per quart (32 ounces) of water. Approximately one quart of water per ounce of pasta recommended.
There are three teaspoons in a tablespoon. So you would use 1 tablespoon of salt for 3 quarts of water. 1 tablespoon per quart would make it too salty.
Because this post is public, I'm obliged to add that this is about a liter of water for 113g of pasta. 6g of salt per liter.
Now you (I) will never need to google this information again. Just ctrl-F "pasta" or "spaghetti" or "salt" on the main page and you'll always be able to find it (I will, this post is exclusively for future me)