Copyright
Quoting the book or using some of the ideas/puzzles, etc in a chess book are obviously not illegal but to directly scan and publish a picture of a page of the book is probably not a good idea... I'm not sure how internet law works exaclty but I'm assuming if you are accessing the site from a particular country that has specific copyright laws you are probably pushing it.
If someone asks me a question in a message or in chat and I have the answer in a book, can I scan it and post it to them without infringing copyright (seeing as its a private message)? What is the rule for blogs where many people can view? I have noticed some books available to download also. What is the rule on this please.