xkcd.WTF!?

Explanation ➲

In the US, people in various parts of the country refer to carbonated beverages by different names such as "soda", "pop", "coke", and others. Generally, the West Coast and Northeast say "soda", the South says "coke" and the rest of the country says "pop". There are various maps of where these different names are used, including popvssoda.com and this map on Laughing Squid. Such maps were trending and popular in 2013.

xkcd's map is a satire of those maps – these regional terms are fake. Not only are there far more terms than are actually used by Americans, many are terms for other beverages (mead), unrelated liquids (quicksilver), or trademarked beverage names less popular than Coke/Coca Cola (Code Red) – and in one case, something that's not even tangible ("Crypto").

Map terms (from left to right, approximately)

Fanta	Name of a carbonated beverage line, manufactured by Coca-Cola.
Söde	Presumably pronounced "soda" but spelled oddly (might be reference to Monty Python and the Holy Grail subtitles - "Wi nøt trei a høliday in Sweden this yër?"). Or it could be a Heavy Metal Umlaut.
True Water	Possibly a reference to Tru Blood, a fictional artificial blood substitute for vampires in The Southern Vampire Mysteries book series by Charlaine Harris, and the television series True Blood. Also could be a reference to "purified" mineral waters such as Smartwater.
Crypto	Popularized as a slang term in the late '80s and early '90s to refer to anything involving the act of encryption/decryption through the application of ciphers, a practice which has become practically ubiquitous in the digital age. Given the highlighted region is the Silicon Valley, this is almost certainly a reference to cryptography and/or cryptocurrency. None of these concepts are liquid and therefore not drinkable. Possibly a joke that the residents of Silicon Valley are actually computers that "drink" crypto (i.e. data). Might also reference the fact that it creates bubbles.[citation needed]
Yum	Refers to Yum! Brands, parent company of several fast food restaurants, which was spun off from PepsiCo, maker of a carbonated beverage, in 1997, and has a lifetime contract to serve their beverages.
Sparkle Fluid	Roughly analogously to how "sparkling wine" and "sparkling cider" are carbonated varieties of wine and cider, "sparkling fluid" or "sparkle fluid" would presumably be any carbonated fluid
King Cola	Name of a carbonated beverage.
Pepsi	Brand-wide name of a carbonated beverage that (as with the handily single-syllable "Coke" in real-life contexts) clearly extends across all other brands throughout most (see below) the Hawaiian islands.
Crystal Pepsi	Sub-brand name of a particular carbonated beverage. Being local to one of the Hawaiian islands (see above) as an even more highly-specific 'generic' name being used for no apparent reason. Its syllable count makes it no more convenient to say than most other brand names and even many sub-varieties, directly.
Ichor	Several definitions: blood of a god, or demon, or, in some dialects, any insect; or watery discharge from a wound. None of them carbonated. None of them recommended as a drinkable beverage. (Well, not by someone with your best interests at heart.)[citation needed]
You-Know-What	A phrase typically employed when a more specific term is considered unspeakable or taboo. Possibly a reference to Harry Potter and You-Know-Who (Voldemort).
Tab	Name of a carbonated beverage, manufactured by Coca-Cola.
Spicewater	Thought to be a reference to the spice in "Dune." This area covers much of the state of Idaho, which may be a reference to the character Duncan Idaho in Dune.
Softie	Short for soft drink. On the map, it looks like the region for Softie is being punched by the region labeled Punch.
Ohio Tea	The area in question covers much of Arizona, the namesake of Arizona Iced Tea, itself a non-carbonated beverage. This implies that residents of Arizona view carbonated beverages as something that comes from Ohio, and thus they place Ohio's name before the word "Tea" to indicate its carbonated state. Could also refer to "...bubbling crude. Oil that is, black gold, Texas tea.
Boat Drink	A reference to the song "Boat Drinks" by Jimmy Buffett.
Melt	Usually used to describe a kind of sandwich where cheese is melted in the center, usually on a griddle. Possibly a play on malt drink. Or maybe just a way to say "no, the *melted* ice".
Fizz Ooze	Fizz is the sound made when opening a sealed carbonated beverage. Ooze means a slow trickle out of a liquid.
Punch	A beverage typically found in the juice aisle. Only sometimes carbonated. It's also a pun on the word punch, meaning to hit something, and on the map it looks like the region for Punch is literally punching the region for Softie.
Fun Wine	Implies that normal wine is not "fun". Might be an allusion to Cheerwine, a carbonated beverage from the Southeast.
Diet	Sometimes refers to a carbonated beverage. A common request in restaurants, as they often only have a single "diet soda" option for customers to pick.
Refill	A subsequent glass of whatever you drank previously. Works for any drinkable liquid. Some restaurants do not require extra payment for one.
Tickle Juice	Name of a Boston-based jazz band. Perhaps a slang term for alcohol, as it "tickles" the tastebuds.
Bubble Honey	A honey-based drink with bubbles?
Sugar Oil	Some sodas do contain oils such as palm oil. The areas of Oklahoma and north Texas that are shaded produce a significant amount of crude oil.
The Wet Drink	Technically true of all beverages, unless one is attempting to drink sand (or anhydrous fluids - of which the least harmful may be clarified butter). It may also refer to the fact that many advertisements for carbonated beverages attempt to make the product look more appetizing by photographing or filming a beverage container covered with water droplets.
Code Red	Name of a carbonated beverage. The cherry flavored version of Mountain Dew.
Mead	An alcoholic beverage. Traditionally not carbonated. Often associated with Vikings, and these areas did have many Scandinavian immigrants.
Canadian Ale	Probably a reference to the Canada Dry brand of Ginger Ale, a non-alcoholic carbonated beverage.
Aether	In antiquity, "Aether" was a hypothetical liquid believed to carry light waves, before electromagnetism was better understood, and also used as a term to refer to the sky or heavens; "Aether" could refer to diethyl ether, a highly flammable industrial solvent, also used as an anesthetic. Neither is carbonated in its liquid form, and neither would be safe to drink as a beverage.
Carbonated Beverage	Technically correct, but a bit of an awkward term due to its unnecessary length. Carbonated water with no sweeteners or other additives is labeled as seltzer.
Mouthwater	A play on the term "mouth watering" to describe delicious foods and beverages. Alternatively may refer to spit, water from the mouth, or that it is a liquid one puts in their mouth.
Capri	Capri Sun is a brand of beverages flavored with fruit juice, typically sold uncarbonated in pouches.
Skim Shake	A shortened name of the beverage "Skim Milkshake".
Kid's Coffee	Somewhat accurate. Coffee is typically drunk by adults for its caffeine. Carbonated beverages often have caffeine and are often consumed by children. Possibly a reference to the song "Kids" from the 1960 musical Bye Bye Birdie.
Regular	Refers to regular soda containing sugars (as opposed to diet), implying that your only choice of beverages is between regular or diet soda. In the past, "Regular" sometimes referred to gasoline containing lead, as opposed to "Unleaded" gasoline. It was not carbonated, nor safe as a beverage, and is now outlawed. Could also refer to regular coffee (in some places referring to caffeinated coffee having one milk and one sugar added, or as opposed to decaffeinated coffee), which is a beverage that is not carbonated.
Tang	An orange-flavored beverage containing less than 2% juice extract. Normally sold in powdered form, and not carbonated.
Formula	Typically refers to an artificial replacement for mother's milk. Not carbonated.
Medicine	The syrups used to flavor colas were originally produced and sold for their (allegedly) medicinal properties - indeed, the very word "Pepsi" was derived from it being touted as an effective remedy against dyspepsia (now more commonly called indigestion). Likewise, tonic water, a carbonated quinine solution, was originally used to treat malaria. (This may have led to "tonic" becoming the traditional Bostonian word for soft drinks - although this is changing.) It could also refer to modern uses of Ginger Ale as a folk remedy for an upset stomach, or to the practice of chugging a carbonated beverage to relieve bloating by inducing burping.
Broth	Liquid in which bones, meat, fish, or vegetables have simmered. Often used as a soup base. Not carbonated.
Fool's Champagne	Carbonated beverage is to champagne what fool's gold (pyrite) is to gold.
Sugar Milk	Possibly a reference to sap extracted from the stems & trunks of plants, which is sometimes called "milk", such as "dandelion milk"; Under this convention, a beverage made from the extract of sugar cane stems could be termed "sugar milk". Also, food-grade liquids that superficially resemble mammalian milk are often labeled as "[X] milk" after their source, such as "soy milk" and "almond milk"; Sugar being a major component of milk & milk substitutes, it may make sense to call soda "sugar milk." Possibly related: In this region of the US, people drink a popular carbonated beverage called Moxie that may be less familiar to people elsewhere.
No word for them	This region of the US does not have a word for carbonated beverages (according to Randall). It's not uncommon for speakers of a dialect to be familiar with something but have no specific term for it; for example a rainstorm while the sun is still shining is called a "sunshower" in some dialects, but in other dialects it is just a rainstorm. Randall could also be suggesting the citizens of Vermont do not even have carbonated drinks at all, thus their dialect would never develop a word for them.
Hydro	A word for water. Carbonated water does exist, but this word means all forms of water. Possibly a reference to the film Waterworld, in which "hydro" is the common term for (scarce and valuable) drinkable water.
Harvard Tea	The region shaded this way includes Cambridge, Massachusetts, which is home to Harvard University.
Bubbler	A nod to another popular map of the same type, exploring the regional dialects used to describe drinking fountains. Rhode Island and the eastern portion of Wisconsin are the only two locations where 'Bubbler' is commonly used to refer to drinking fountains, but the word is commonly used in surrounding areas to depict the strong variety of rhoticity present, some saying 'bubblah' in for example Boston, and others saying 'water fountain'.
Mouthbuzz	Perhaps referring to the feeling of drinking a carbonated beverage, where the releasing carbonation almost 'buzzes' in the mouth.
Brad's Elixir	Possibly a reference to "Brad's Drink", the original name for Pepsi when it was invented by Caleb Bradham in 1893. The word "elixir" is defined as "a sweetened liquid usually containing alcohol that is used in medication either for its medicinal ingredients or as a flavoring". "Elixir" was misspelled in the original version of this comic as "elixer".
Hot Water	Not carbonated. Not even in Jacuzzi and hot tubs. May reference how boiled water forms bubbles before it actually comes to a boil.
Fluid	A word that means nearly any liquid or gas in existence. Not specific to carbonated beverages.
Coke Zero	Name of a carbonated beverage.
Carbo	Sodas sweetened with corn syrup or cane sugar are high in carbohydrates. Could also refer to carbonation.
Quicksilver	An old term for the element mercury, a metallic liquid in its pure form at room temperature. It should also be noted that mercury is a toxin and in most cases it is medically contraindicated against drinking mercury as a beverage.
Glug	Onomatopoeia, referring to the sound of swallowing a large amount of liquid. Or possibly referring to glögg (pronounced "glug"), a Swedish beverage similar to mulled wine.
Water Plus	Technically the name of a British water retail services provider, this likely refers to the prevalence of "plus" as a preposition in branding nomenclature (e.g.: Google+, iPhone 8 Plus, 7 Up Plus, etc.). Also reminiscent of "Milk Plus," the drugged milk from the movie A Clockwork Orange.
Carbo bev (title text)	Not actually popular, but used by one person trying to sound hip and trendy, to the ire of his peers. Randall states this guy lives in Missouri — in real life "Coke" is used for most of the midwest, except an area centered around St. Louis, MO where "Soda" is more popular (see the maps linked above for more details).