We get this question from marketing managers a lot. Yes, posting duplicate content does matter. In fact, it can bring your page down in the results on search engines. Effective SEO requires content to be continually fresh , refreshed, or redirected to achieve the best ranking results.
Posting the same page over multiple URLs doesn't work.
Google and other search engines will always attempt to determine which version of the page is the most up-to-date. This makes sense — no user wants to see a results page with 25 hits returning the same content. So if you are posting the same page but modulating your URLs or your click-tracking code, the search engine is just going to pick a version and default to it.
Streamline your pages as much as possible.
If you have several pages that share quite a bit of content — let's say, the same phrase or paragraph repeated several times over a number of subpages — streamline the similar content to one page, then branch off that node into other pages where there will be differentiation.
So, if you are a bookseller, and you are offering several books by Jane Austen, you wouldn't want to repeat her short bio on each book's sales page. You would want to branch her individual books' sales pages off her author page, or have a link to her author bio page from each sales page. Either way, you are avoiding duplication.
If you are providing content to other sites, make sure they are linking back to you.
Let's say that you write an article that is to be published across a blog ring, or across multiple news aggregating sites. There's a problem: the search engines are reading the words in your document or on your page and could tag your original work as duplicate to a site that is, in fact, republishing your work.
Again, search engines will pick one posting area and defer to this. Even if you are licensing the content out, if there is no link back to the original producer, the search engine doesn't know where to default or how to appropriately assign rank.
Search your content often and avoid being plagiarized.
There are unsavory sorts out there who will flat out lift your content and pass it off as their own. If you are not diligently searching your recently-posted content for the first several days or weeks (depending on how often you post and how much fresh content is driving your site traffic), you risk your site's rank falling by the wayside. Make sure you defend any of your copyrighted content vigorously.
When you update or tweak old pages, code in a redirect.
Yes, of course, you want to update older pages when the information therein becomes stale or goes out-of-date. But you shouldn't copy the information, edit and post it under a new URL on your site without deleting the older page, or redirecting from it. If you fail to do so, the pages will detract from each other's rankings scores. But if you do redirect, the hits on the old page will actually augment the ranking score for the newer page.
If you rewrite something, rewrite it. Don't tweak a word here and a word there.
Changing a few nouns and verbs, or adding and subtracting a sentence or two, then reposting an article under a different title does not fresh content make. And the search engines will penalize you for it.
If you are going to update previously published content under a new title, simply re-read the older piece and re-write with it in mind, but out of site. You may find a few fresh ways of saying something that you hadn't thought of the first time around.
Revisit earlier ranking results and use them as a guide for revisions.
If you're refreshing or updating your older content, review the metrics from the earlier piece and take this opportunity to rethink your SEO keywords. Which phrases or words brought in the most traffic before? Were there some search phrases that were ineffective and could they be effective if revised, or should they be dropped entirely? Are there better or more up-to-date terms you could use? Are there a few applicable buzzwords that have developed in the interim?
Yes, Virginia, that is a duplicate clause. De-rank it.
Of course, we always advocate you stay on top of your site's traffic and with trends in your market, that you use the data you gather as a guide for generating fresh content and that you avoid re-hashing whenever possible.
But for those times when you really need to re-post or revise something, be savvy to the potential effect on your ranking results. Make sure you redirect from older pages or delete them when they become obsolete and streamline your content wherever possible.