A WebmasterWorld member notes that when he does a link: query for a specific domain, it shows only internal links and not external links -- but it depends on the size of the domain. This behavior is only observed on very large sites versus smaller ones. How come that's the case? Is there an issue of how this data is being gathered and is there extra weight being placed on these links?
Tedster believes that this isn't the case. He says that internal links pass PR around the site but that the internal linking structure is not weighted as heavily as external links:
Internal links do have anchor text influence, and they do pass PR around the site. But I'd say they are not treated "exactly" same as external links. How exactly their treatment differs is a bit of a Google secret, and it also seems to shift around a bit. For example, I'd say many internal links get a lot less individual weight than a single external backlink would, especially if they are in the page template (menus and footer links.)
On that note, some internal links can be more valuable than external links depending on PageRank, popularity, traffic, and more. Your PR5 homepage internal link will probably be a lot more valuable than a PR0 external link from a link farm. Do you agree?
Forum discussion continues at WebmasterWorld.