Originally, the only Caputo flour that was available to the members of the forum was the Caputo 00 Pizzeria flour. That is the one shown in at the Molino Caputo website in the bag with a picture of a pizza on it. Because that flour was the only Caputo 00 flour we were aware of initially, we simply referred to it as "Caputo" flour or "Caputo 00" flour.
Subsequently, another Caputo flour was introduced to the U.S. market, called Extra Blu. That is the flour shown at the Molino Caputo website in the blue bag with a picture of a wide variety of baked goods. The Caputo Extra Blu has lower protein content than the Caputo 00 Pizzeria. It can be used for broad baking applications, as suggested by the picture on the bag, but it can also be used to make pizza where the dough has a short fermentation time. To distinguish between this flour and the Pizzeria flour, many of us have started to refer to the flours by their full names.
There is also a third Caputo 00 flour that is available in the U.S. market, called Rinforzato Rosso. That's the one that is shown in the red bag at the Molino Caputo website. It has a higher protein content than the other two Caputo flours discussed above. It also can be used to make pizza dough, mainly those applications benefiting from quite long fermentation times. To the best of my knowledge, very few of our members use that flour. The Rinforzato Rosso is often simply called "Caputo Red".