Why copyright infringement is wrong?
Sharing quotes and images from other blogs is what most content creators are fond of doing. Whenever they find an interesting article, they rewrite it without thinking whether what they are doing is right or wrong. I have never recommended anyone to do that. It is basically stealing other people’s ideas instead of delivering your own. It is just bad manners.
The importance of copyright is increasing, especially for those who do blogging as a business. Getting caught up in copyright infringement lawsuits will cost you a lot. Whenever you feel like you don't have a direct permission to use a particular piece of information on your website, it wise to give credit and link back to the original content owner. It adds value and in most cases makes him/her visible to other users.
I suspect that most people don't provide links. I would refer to this as to a "sleazy rewriting trick", as they would never link back to the content owner because they might get caught. Moreover, the reader may compare the stolen article and the original content and be like "The items are similar. They just added a few words to the initial content and that's it."
It is always good to ask for permission. Including quotes and excerpts from some of your favorite blog posts is allowed, provided that you link back to the original author. If you are sure your content is original, you can quote other sources as a contribution to your ideas without feeling guilty. If you feel guilty linking back to the source that you used to write a paper, the best advice is to go back and rewrite an article again.