Duplicate content q - Can search engines tell where the original text was copied from?

[Sparkstone]

I was under the impression that when a search engine comes across duplicate content it won't be able to determine which one is the original. Is this not the case?

[DougRoberts]

Not sure canonical tags work that way! You use the canonical tag to provide the search engines with the "official" URL of your content. This is especially useful when you're using a CMS that delivers your content on a number of alternate urls. It won't help search engines determine the "owner" of the content.

Matt Cutts has said that Google is getting better at identifying the original owner of the site, but it's not perfect. Google don't have a magic way of seeing everything that goes on, they have to crawl which takes time.

I don't know if it would help if you manually submit your page to google using the Google Webmaster tools / fetch as googlebot option as soon as you purplish your page. Might help get your page into the index first. Not exactly a scalable approach if you're publishing a lot of material though.

One of the best ways of protecting yourself is to embed relevant (absolute) links into the body of your content pointing to related articles on your own site. One website I'm working on gets a surprising number of referrals that way! Oh,also think about adding links to your new content from some of your older content, if it's relevant and makes sense to do so.

Authorship markup might also help.

[Sparkstone]

What if both sites added canonical tags on their content?

[Feily]

That all depends if the site that you have taken the content from has placed canonical tags on there content which says that  there site was the original owner of the content. This means that you will get seen as having duplicate content and they wont.