Well sir, if you read the FAQ of every forum you dig around in I applaud you. Frankly I see no need to read an FAQ till I have a question, as one forum is pretty much like another. I'm more likely to read the Sticky topics with posting guidelines. If you will note, I did read the FAQ once I had a question, "Why can't I sign-up for an account? What does this error mean?" Also, the FAQ is not indexed by the search engine. I had assumed such and would hence not have needed to read the FAQ separately, but obviously I was in error. Now, the real issue is, why is such important information for signing up not on the sign-up page? Furthermore, the FAQ actually does not link banned email domains to trouble signing up, merely to getting an "invalid email" PM. Also, if you will note, I mentioned the particular error message "Error 578" which is not mentioned in the FAQ as being caused by a banned email domain. So, really I fail to see what you are getting at as, A) I did end up reading the FAQ once I had a question, and B) the FAQ only indirectly answered the question by deductive reasoning. 
edit: spelling