Google engineer and leader of the webspam group Matt Cutts is back in this Grab Bag video to answer a question regarding linkage. One webmaster was curious to know whether Google links have any worth at all in terms of Page Rank as he observed that they are never shown under Webmaster Tools. The examples cited include Google Profiles and Bookmarks.

Matt quickly counters that this observation does not hold true for all cases. He says that in his experience, the link to his site from a Google blog roll do get listed on the GWT. In general, Google is extremely careful when it comes to flowing page rank because the public expects them to do everything at a high standard. Even small errors can be noticed and generate controversy so they tend to have their massive portfolio of online properties on a tight leash.

 

Google engineers always try to minimize their sites’ vulnerability to spamming but some by their very nature are prone to abuse. These tend to use the no follow attribute to curb abusive behavior – which might explain the case of Profiles and Bookmarks. Sometimes sites start out with a total blockage policy as in Google Knol but evolve into selective link flow for people who have earned a good reputation. When it comes to search results, they make sure that no link juice is leaked in any way.

Video Link:
Does Google value its own links for PageRank? –