Most technical books do go out of date pretty quick. But at the time they served a need. Most of them are dated now, however not all of them are door stops. I won't get rid of them though.
Most/all information can be had by doing a google search. But a book can be nice to have. Its portable, you can write in the margins, you can give a book to another person. Its great when I am in place with no internet connectivity, like the beach. Yeah , I read about Postfix when I am at the beach, and Samba too.
My other library is larger and is either fiction or non-fiction, soft-cover and hard-cover. There are some books I have read multiple times, and some of them only once.
But I like books. I like the paper, and the feel of the pages. Its like the difference between an analog clock and a digital clock. I will take analog each time.
I have friends that don't buy books. Thats what a library is for, so they tell me. I suppose that is true, but I like walking across the room and just pulling one off the shelf. I read 4 books at a time, at my leisure, at my pace. Getting information off of an LCD display is efficient and cold, and there is nothing wrong with that. But I can't curl up on the couch with a 20" LCD.
Give me a good book, a cup of coffee and a Saturday afternoon. I am happy.