U.S. Internet giant Google\'s social networking Web service Google+ is adding 4,375,000 users every week, an unofficial monitor of the service said. The estimate, made by Ancestry.com founder Paul Allen, is unofficial. ComScore reported last week the number of unique visitors checking out Google+ in November was 67 million, up from 65 million in October, the Los Angeles Times reported Wednesday. \"Unique visitors\" are different from \"members.\" Google said in October Google+ had 40 million users. Rival Facebook says it has more than 800 million users, but Allen predicted Google+ will have half that many by the end of 2012 -- a fast start for a Web site that was launched in June.