There are plenty of things I think could be updated about CL, and I wouldn't recommend LispWorks as a first place to start either. But I think you'd have to be part of a really niche area of tech to consider the very concept of reading books to be obsolete. If I want to get into a new language, the first thing I look for is whether there is a good introductory book, vs. just a scattered set of HOWTOs/READMEs/Wikis.
However there are books online as well, nowadays, if you really prefer to read on a screen. Seibel's Practical Common Lisp is a good starting point: http://www.gigamonkeys.com/book/
I don't think the point was "reading books is obsolete" so much as that only having printed books as references presents a hurdle to the would-be Common Lisper. A language that has good free tools and online documentation available is a language that you can start playing with right now, the moment the desire strikes you, which encourages new people to join the community. If you have to wait for a book to arrive or shell out X thousand dollars to get decent tools, some non-trivial percentage of interested people will decide it's not worth doing those things and move on.
It's just that these books are 'old'. Common Lisp is 30 now. But since the core language does not change much, the old books are still fine. They may smell a bit.
I'm biased toward reading dead tree books - last month I paid 99 cents for The Standard C Libary, so I take that into account.
What I also take into account is StackOverflow. There are a lot of programmers who don't even read a page of google search results.
I will also say that from my time on HN, the number of people who read dead-tree technical books versus the number who read ebook versions of technical books may be less than dead even. They're cheaper [new] and services like Safari provide entire libraries at reasonable prices. [I've commented elsewhere in this thread on how Seibel's book exemplifies the some of the Common Lisp community's tone deafness].
I wasn't suggesting that Lisp programmers tend to page fault into learning. I apologize for not being clear.
What I was getting at is that StackOverflow shows that many programmers in general tend to page fault into learning whatever language they happen to be using. This is a behavior which StackOverflow is explicitly designed to facilitate. It is also designed to facilitate the behavior in ways that are better than traditional Usenet and its web-based descendants in the form of fora.
Recently I've listened to nearly all of the StackExchange and StackOverflow podcasts - as a tangent this includes the one's where they discuss updating the FAQ, the contents of the old FAQ why it was obsolete, what the new FAQ needed to accomplish, and of course the contents of the new FAQ as it evolved.
One of the reasons that I listened to all of those podcasts is that I found Spolsky's and Atwood's ideas [1] about online communities insightful and was able to relate them to my experience in other online communities. I recommend them to anyone who shares my interest.
[1] and those of their guests and other team members.
However there are books online as well, nowadays, if you really prefer to read on a screen. Seibel's Practical Common Lisp is a good starting point: http://www.gigamonkeys.com/book/