There was an interesting question about why Google would only show one of two sites that are unique but can rank for similar queries in the same set of search results. John Mueller of Google said normally Google would show the two sites, even if they are similar, even if they have the same ownership. So it might be another issue.
The specific sites were not named, so it made it hard for John to answer. But I know of many sites that this can apply to. For example, a search on [Jordan Retro 9] brings up search results from both footlocker.com and eastbay.com – both owned by Foot Locker, Inc and both rank just fine.
The specific question came up at the 14:52 mark where the question was around why Google started to take two sites that have unique but similar content and not show one of those sites in the search results. Google instead hides the other site in the “omitted results” section.
Here is a screen shot of what he means by omitted results:
The specific question was:
John said without looking at the specific query and sites, it would be hard for him to know. He did say “usually with two websites if they’re not completely the same then we would rank them individually, even if there is kind of like an ownership relationship there.”
He thinks there may be something else going on and asked him to post more details in the Webmaster forums.
Here is what John said:
Here is the video embed:
Forum discussion at YouTube Community.