I am not sure all of these articles or accurate. Anyone can correct it, if one or more of these articles are wrong.
This blog gives a good glimpse of Di Fara’s. https://homeslicepizza.wordpress.com/2010/10/01/the-mythic-difara/
This article says:http://kitchenproject.com/history/pizza/index.htm
Pizza Only Became Popular in the US after WWII
"Pizza came to America at the end of the nineteenth century with immigrants from southern Italy. Italian immigrants built commercial bakeries and backyard ovens to produce bread they had eaten in Italy. In addition, Italian bakers used their ovens for flatbreads: northern Italians baked focaccia, while southern Italians made pizza. Initially, pizza was made by Italians for Italians, but hy the late 1930s after the Great Depression many Americans were eating pizza in Italian restaurants and pizzerias on the East and West Coasts...Over time, two basic and distinct styles of American pizza appeared. A thin-crust pizza, commonly called "East Coast" or "New York" style, is made with just a few toppings like pizza made in Naples.http://whatscookingamerica.net/History/Pizza/PizzaHistory.htm
NOTE: For many people, especially among the Italian-American population, the first American pizzas were known as Tomato Pie. Even in the present 21st century, present-day tomato pie is most commonly found in the Northeastern United States, especially in Italian bakeries in central New York. Tomato pies are built the opposite of pizza pies - first the cheese, then the toppings, and then the sauce.
1905 - Gennaro Lombardi claims to have opened the first United States Pizzeria in New York City at 53 ½ Spring Street. Lombardo is now known as America's "Patriaca della Pizza." It wasn't until the early 1930s that he added tables and chairs and sold spaghetti as well.
1943 - Chicago-style deep-dish pizza (a pizza with a flaky crust that rises an inch or more above the plate and surrounds deep piles of toppings) was created by Ike Sewell at his bar and grill called Pizzeria Uno.
1945 - With the stationing of American soldiers in Italy during World War II (1941-1945) came a growing appreciation of pizza. When the soldiers returned from war, they brought with them a taste for pizza.
1948 - The first commercial pizza-pie mix, "Roman Pizza Mix," was produced in Worcester, Massachusetts by Frank A. Fiorello.
1950s - It wasn't until the 1950s that Americans really started noticing pizza. Celebrities of Italian origin, such as Jerry Colonna, Frank Sinatra, Jimmy Durante, and baseball star Joe DiMaggio all devoured pizzas. It is also said that the line from the song by famous singer, Dean Martin; "When the moon hits your eye like a big pizza pie, that amore" set America singing and eating pizzas.
1957 - Frozen pizzas were introduced and found in local grocery stores. The first was marketed by the Celentano Brothers. Pizza soon became the most popular of all frozen food.
Another article about NY style pizza and time lines, if you go down on page.http://www.experienceproject.com/stories/Am-Welcoming-You-To-Kik-Culinary-Corner-And-History-Of-Some/866541