Facebook users crown O2 arena top London landmark According to the social network, the high profile concert venue is the most popular place for Facebook users to check-in to when in the capital. Coming in second place is Oxford Street, followed by Leicester Square, Covent Garden and the Emirates Stadium. The seven other cities featured in the list are: Berlin, New York, Melbourne, Paris, Sao Paulo, Tokyo, Seoul and Tokyo. The most popular landmark in New York is Times Square, followed by Madison Square Gardens, Central Park, the Rockefeller Centre and the World Trade Centre site. And in Paris the Eiffel Tower was beaten to the top spot by the Avenue des Champs-Elysees. Facebook's check-in button on the mobile app encourages people to share their location with their network and tag friends who are with them in posts. Originally the social network tried to cash in on this activity through "check-in" deals - which offered discounts based on the frequency a user visited a shop or restaurant. However, the deals have yet to take off. Nor has Facebook moved beyond the big corporate chains and engaged smaller local merchants in the UK.