The answer to all of this concerns the nature of the Hebrew language. When you play Scrabble in English, if you pick up five letters at random (that is the average length of an English word), the letters are almost always nonsense, like ssdfji or jkntu. It's rare to get a word. But in Hebrew, the average length is three letters, and you do not need to write vowels. There are 22 letters in the Hebrew alphabet, giving you just over 9000 different words. Look at the back of your Strong's concordance for the count in the dictionary back there, and you'll see 8000 of them are in the Bible. That's about how many words a language needs to be a language, anyway. That means, you get a word at random in Hebrew almost all the time. Now there are almost 10,000 words in OT (so Google tells me). Thats's about 30,000 letters. Now, the programs that make the codes let you start anywhere, go forwards or backward, and skip any number of letters between the ones you use, up to 50. That gives you 3,000,000 ways to come up with a possible selection of letters. With almost a 90% chance that a string of three letters means something, there is nearly a 50% chance that a group of five words means something. That means, the OT run according to the code program produces nearly 1,500,000 possible sentences.
I was totally amazed at how, when I did historical research into revivals, the two century old newspapers had mostly the same other news as we have today. Names and places change, but otherwise the headlines are about the same.
Now, how do humans process potential prophecy generated from random events? Here's an experiment: Take a pad and pencil, an all night radio talk show, and some cheap paperback novels. Listen to the talk show, read the books, and anytime you hear the same word at the same time your eyes see it, write the word down. I am told you always get a "prophecy" at the end of several hours. It's like a ouija board. By the time someone in the circle sees the first few random letters, they control the rest of it subconsciously.
Put this all together, and you get a predeliction to seeing "prophecies" in random data, a method of coming up with a thousand times as much information as history seems to indicate ever was published, and a fancy new gadget (the home computer, at the time) to give it to you.
The "Bible Code" is the end product.