You can enter a short message (up to 100 characters) and it will be laser projected in New York, Mumbai, Rio, or Geneva.
In New York and Mumbai, it's projected onto the side of a building. In Rio, they project on the side of a mountain. And in Geneva, it's on the Jet d'Eau, a fountain that shoots a 460-foot tall plume of water from Lake Geneva. Yes, they actually project onto the water, and the message is displayed 425 feet tall by 50 feet wide. The projection in Rio is a whopping 1310 feet wide by 230 feet tall.
In addition to entering messages, you can get pretty reliable live video feeds of wherever they're projecting.