Membership in Google+, which was launched only about three weeks ago, is soaring. Calculations by Comscore indicate the service had 20 million visitors in just 21 days. Meanwhile, Google is reported to be preparing to add a social gaming feature to the Google+ service in order to attract even more subscribers and pose a stronger challenge to its primary target, Facebook. However, the addition of social gaming may bring with it more problems about user privacy. Facebook has been criticized for sharing subscriber information with makers of social gaming apps.