How do usenet servers work? (please read details)?

Question by : How do usenet servers work? (please read details)?
I have used giganews with newsbin reader for a couple of months, and tried various search services.

One thing I don’t understand is how every single file I have found in search, I have been able to download. That is probably more that 1,5 TB of files. There are so many server providers that I expected a lot of files not to be accessible to me, in a search with no filter for server provider. I understand that Giganews might be the biggest provider, but this still seems very improbable. Can you explain this?

As a second question I am interested to know is how much data giganews has stored on their servers, and what the collective size of all unique files shared in newsgroups is.
I will write this again PLEASE READ THE DETAILS. I have specific questions, and I am not interested in general information about usenet.
Please DO NOT SIMPLY ADD LINKS that MIGHT have an answer. If you want to answer, please do so after reading the details.

Best answer:

Answer by Ken

Here are a couple of links for starters…

These should be good places to start.

What do you think? Answer below!