When I started reading the books, ~2 years ago, there were not yet many. So I guess I would be surprised now to find new ones. And I did not read all the books throroughly either ... well, I was searching for specific information about communication (quest related), and most other information for daily habits I already learned from friends.
I bet the name "Eagle's Rock" was founded by players long before the book about it was available... And that may be only the most famous example. Most names reach me rather by word-of-mouth than by reading any books. Or by ripping apart the data files: Before I read the name "Korogan", I used to call the green glowing passages "Jade gate" (when there was only one).
Books in the library are definitely a useful resource, regarding roleplaying. I am happy when I can tell a newcomer to "go to the library and read a book" instead of telling him to [ read the forums ]. I wish I may be able to read some of our favourite drinks and receipes there, as they were collected here in the forums. (And someone tell Jomed how to make a "Cumbana Split"!)
And if there was no "Death Penalty", I would even try and look if there are any readable books in the Library of the Dead. But for now, sorry - no way. I'm staying alive.