Recently there was kind of a discussion, with one user being a bit mean towards the other regarding the latter posting a link to Amazon.

While I do not agree with how they brought the discussion, I think it would be great to read everyone's opinion about what should be link, and if linking to specific websites should be forbidden.

For example, we have Open Library, BookWyrm, Inventaire, etc, if you only want to link to a book's information, and while it is harder to find a replacement to a web site where you can buy books, users can always search for it if they want.

What are your thoughts?