roomshares are at the low end in real estate because the typical user doesn't spend a lot of money. My strategy would be to get as many listings as possible, even if that means writing them down from black boards at the university (you might get into trouble copying them from newspapers). Users go to the website with the most listings. Who knows at some point a real estate portal or newspaper might be interested in acquiring that business. Not necessarily because of the roomshares, but you've shown you know the market and can build good websites. Or the real estate portal is behind on their mobile strategy (lots are). The company I worked for competed heavily on SEO and SEM in english speaking markets in real estate ("buy house in <cityname>" etc) and the competition is insane.