The method of kashering (making kosher; removing the blood), is stated in rabbinic sources as follows:

"We wash, soak, salt, and rinse the meat, then throw it into a pot"

We have two major interpretations of this statement. The more common and accepted one is that this is a description of our standard Kashering process. The "throw it into a pot" is really saying that after this process, the meat may even be boiled. There is little question that raw meat may be eaten without kashering, as long as the surface blood is washed off. When boiled, the blood leaves the flesh, becoming forbidden at that point. It is then reabsorbed during the cooking process, rendering the meat unkosher. After soaking and salting, this is no longer a concern. What about the blood we see even after cooking? That is only "juices", not true blood.
An opposing view, expressed by certain medieval rabbis, and championed by RAMBAM, and followed by the Yemenites even today, says that this is totally a wrong interpretation. Salting does NOT remove blood, except to a depth of about a centimeter. One must soak and salt the meat to remove the blood near the surface. Then, the meat must be plunged into boiling water, thus sealing in the blood that is in the flesh , so that it will not be able to become forbidden by becoming separate. After a short period of boiling, the meat is good to go. While the Talmud, when speaking of broiling, says "the fire draws", no such statement is found about salt until several centuries after. According to this interpretation, virtually all meat dishes are actually non kosher! At one time, this process, known as Halita, was practiced in many places, but eventually, all except Yemen went over to the standard practice. I must say, that this topic caused me angst for many years. I saw meat after kashering. It was clear that salt did nothing beyond a surface effect. The claim of many rabbis that although twenty minutes of salting is enough, the fact that we normally do a full hour, gets out all the blood, is demonstrably preposterous. I asked Sima that any meat we cook at home, be subject to halita. For meat we eat elsewhere, or which is pre prepared (my favorite cut of meat is "tube steak" otherwise known as the "hotdog"), I relied, very reluctantly, on the common practice. When I learned from one of my sons, who works in the kashrut industry, that stores regularly "freshen up" meat that is past its prime by adding blood drippings, my conscience really knew no peace. My world took a drastic turn for the better, when about two years ago, an article on yahoo news had a headline "Blood that drips from meat is not blood". The article stated that virtually all the blood leaves the animal at slaughter. What drips out later is not blood, but myoglobin. Myoglobin looks like blood, but is actually a substance produced by muscle tissue breaking down after death, I confirmed this with several physicians, and a veterinarian. For the first time I understood that when the Talmud says that "dam evarim" (blood of the organs) is only forbidden by rabbinic law, it wasn't referring to capillary blood, as I had thought, but to myoglobin. I realized immediately the amazing knowledge of the ancient rabbis. They wanted us to remove even the semblance of forbidden blood, and required us to take reasonable measures to remove it, but not to go crazy. We still do halita on fresh meat, but only as a stringency. I recall the Talmudic statement "if they (the Jews) aren't prophets, they are still the sons of prophets". One more issue regarding blood, is blood found in eggs. That will be my next topic.