Duplicate content is harmful to website. it continues means spamming your website.

The Site gets penalized if the Search Engine Bot finds duplicate content in the site.

Duplicate content is content where you can find the same content on one or more different sites. Many new bloggers, including me, when I started my blogging hobby, those days, I also used to copy the content from others site, actually many new bloggers don’t know, what happens when they copied from another source.

If google found duplicate content this is not mean google will penalize you. You have to just provide link back to the website from you have copying content. Its known as link baiting and with this, chances of penalty get down.

Useful information about duplicate content, thanks for sharing.