This has come up twice in as many days: What do you do if you have two separate but connected businesses with similar websites?
The first situation was like this: a very large e commerce site had just acquired another large company. Many of their products overlapped, but not all. Due to some of the supplier agreements with manufacturers they couldn’t just consolidate into a single site. So why not have a central database and pull the same products to either domain?
The second was a bit different. This is a service based company who is breaking off a portion of that service into an independent organization. The first would still offer those services in certain situations, so he wants both to be able to rank.
The problem that comes up with both of these situations is duplicate content.
So, to answer both, we need to understand what duplicate content really is. The Google Webmaster Central blog gave a great answer in 2008. Read it here. The quick version is that there is no penalty per se for duplicate content. Rather, search engines take all that content, lump it into one group and only deliver the one they consider to be the “best.” Here’s my favorite part of the article:
Most search engines strive for a certain level of variety; they want to show you ten different results on a search results page, not ten different URLs that all have the same content. To this end, Google tries to filter out duplicate documents so that users experience less redundancy.”
It’s commonly believed that duplicate content will lead to active penalties. In fact, unless you’re purposefully stealing content or using it in an attempt to manipulate rankings, there will only be a passive loss of ranking potential.
For the first client I mentioned, this means that by serving identical product listings on both domains, he is just reducing the likelihood that both could rank. If he were to create unique content for every product, he would have that many more chances to appear in search results. (On a side note, mirroring products like that is also a problem with Google shopping campaigns, as explained here.)
The second one is a lot easier. From another Webmaster Central post:
While you’re free to run as many sites as you want, keep in mind that users prefer to see unique and compelling content. It is a good idea to give each site its own content, personality and function.
As long as the site is well planned and implemented, there isn’t any reason why both sites shouldn’t rank.