This patent for "Ranking blog documents" seems to disagree:
http://bit.ly/msgrsv
"[0044] References to the blog document by other sources may be a positive indication of the quality of the blog document. For example, content of emails or chat transcripts can contain URLs of blog documents. Email or chat discussions that include references to the blog document is a positive indicator of the quality of the blog document."
Andriy Bihun, the first name on the patent, is still a Google software engineer according to LinkedIn.
That's a good find, but the fact that a Google employee has a patent on using email links to rank blogs doesn't necessarily mean that Google's using it.
