In Social, we are finding great ways to leverage the building blocks we put in place on the Facebook platform. In April, we merged our TripAdvisor and Cities I've Visited apps into one app, better integrating Facebook's users' activity within TripAdvisor and allowing friends to find TripAdvisor more easily on Facebook. In the first half of the year, TripAdvisor published more than 300 million actions generated from member activity on our website or using our App into Facebook's Open Graph. In June alone, we had over 32 million logged-in Facebook users use the TripAdvisor app or be instantly personalized on the site. This traffic level makes TripAdvisor the second most popular Facebook app, according to AppData. These efforts have been very successful in terms of brand awareness, content and community building, and growing our friend-connected member base.
In addition to Social, our mobile initiatives continue to thrive as we continue to invest in and innovate on this fast-growing platform. During the quarter, we rolled out our new iPad app and introduced Facebook log-in functionality. We also launched 30 new free City Guides across iOS and Android, bringing our coverage to 50 cities. As of June 30, we reached over 22 million cumulative mobile app downloads of our TripAdvisor, City Guides and SeatGuru apps on smartphones and tablets, up more than 200% year-over-year. We also grew to more than 27 million monthly unique visitors of TripAdvisor on mobile devices in May. Further, tablet continues to be our fastest grower in terms of mobile page views, sessions and unique users and accounts for more than 3/4 of our mobile revenue. We're obviously pleased with our mobile growth and we are focused on creating a more complete user experience on mobile, which will lead to an even more loyal and engaged user community.