Like most search engines, Google doesn't show too many results from a domain on a single search results pages. Until recently, Google displayed at most 2 consecutive results from a site, followed by a link that restricted the results to that site.
Some recent results show that Google adjusted this policy and it now allows 3 or even 4 consecutive results from the same site.
Google also displays 4 additional results bellow some forum threads and it makes it easier to find more results from a site without opening a new page.
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