Does Google penalize for duplicate blog posts?

[Event36030]

Occasionally, I get asked by another blogger if they can repost (in full) one of our blog posts on their blog as a guest post. I've always been under the impression that Google penalizes this type of behavior, but I haven't seen any evidence. Is this true?

[Allie_Williams]

Would you recommend the rel=canonical tag for other page types as well, like informational pages?

For example, Website B has been given permission by the content-creating Website A to use A's original content on B's site. Should site B be required to include the rel=canonical tag on each URL where they are using copied content?

The content still exists on Website A - is using rel=canonical the best way to ensure they continue to get credit for it?

[Event36030]

Brilliant, thank you!

[KyleChamp]

This should answer your question. Kat rose is asking the question and rand fishkin is answering

The following quote is taken from http://www.katroseconsulting.com/search-engine-optimization/attention-bloggers-should-you-be-worried-about-duplicate-content/

KR: Does reposting blogs on other’s blog sites hurt search engine rankings?

RF: It is possible that if you re-publish your content on another site, it could rank in the search engines rather than your own, original version. A link back is often enough to negate this, but there’s also a technical way to make it work 99.9% of the time and that’s with the “Rel = canonical” tag (http://googlewebmastercentral.blogspot.com/2009/12/handling-legitimate-cross-domain.html). If you use this (or have those blogs you guest post on use it), you can feel very confident that your own post will be the one to rank.

If you feel a little lost at the mention of rel: canonical tags, as many do, I’m going to break it down for you with the help of another great source—my friend and SEO guru, Tisho Richardson, Web Associate at ThomasNet.com (formerly the Thomas Register).  Very simply, you put this type of html tag between the “head” tags on the blog post page of the ORIGINAL post; this way the search engines know that this is the one true original version and should rank this version above all others.  This is an example of what a rel: canonical tag looks like behind the scenes of a website:

For example, with the first scenario I referred to–guest posting on another blog, the rel: canonical tag should appear on their site on the page where the blog is posted.  In the second, where others are sharing your already published content, the tag should appear on your blog page (and always be sure that they link back to your original post).

If you have a wordpress blog, as I do, there is a plugin called “Canonical URL’s”. Once the plugin is installed, you will see a box under the post marked “Canonical”.  In there you put the link to the post."