Social news aggregator and discussion forum Reddit has opened its Australian office as part of an ongoing international expansion push. The physical office, located in Sydney’s harbourside Barangaroo precinct, will house a team tasked with expanding the company’s community engagement and advertising push. One expert says the company could be a tough competitor to incumbents Facebook and Google. Australia is the fourth largest market for Reddit, which already boasts 52 million active daily users globally. The expansion follows the establishment of offices in Canada in March and the United Kingdom last year in September. Its most popular thread in the country, r/Australia, has around 700,000 members. Currently, Australians spend 31 minutes per day on average on the platform and contribute 158 million posts. Around 62 percent of users are aged between 18 to 34, and 28 percent between 35 to 49. Reddit also claims that 40 percent of its users …