Would You Use an Online Library?

langeland asks: "I have a friend who is selling subscriptions to an online library of computer literature (for example Books 24x7 or O'Reilly's Safari). He's trying hard to convince me that a library of 3000 books on anything from introductions to various programming languages and reference books to Windows 2003 Server, or MySQL is actually useful. I don't get it - nobody would read a whole book online anyway, so they can only be useful for trouble shooting ad hoc problems (or am I wrong here?). I'm thinking Google is a lot faster for solving problems at the busy job, and you'll probably find good plain web references on most technologies and stick with them. The price for a subscription to Books 24x7 is 400$ a year/seat! Do You have experience with these online libraries? Are they useful and worth the money?"