By Alexei Oreskovic SAN FRANCISCO (Reuters) – A new feature in Google Incs Gmail will result in some users receiving messages from people with whom they have not shared their email addresses, raising concerns among some privacy advocates. The change, which Google announced on Thursday, broadens the list of contacts available to Gmail users so it includes both the email addresses of their existing contacts, as well as the names of people on the Google+ social network. Google is increasingly trying to integrate its Google+, a two-and-a-half-year old social network that has 540 million active users, with its other services. When consumers sign up for Gmail, the companys Web-based email service, they are now automatically given a Google+ account.