The 1888 hotel in Sydney, so named after the Kodak launched their first box&roll camera, has an interesting way of promoting itself. If you have over 10,000 Instagram followers you can stay one night for free. So says the rules on their own Instagram page which shows off that the hotel is pretty from all angles.
Very smart, since people who travel tend to photograph every angle of their stay, and these days this means they share it on Instagram. Using this natural tendency as their advertising strategy is already paying off. Check the hashtag #1888 on Instagram and you'll find thousands of pretty pictures already.