As the internet grew over the decades, astronomers used it mainly as a tool for remote observing, accessing both distant mountaintops and space satellites. But as web browsers became more powerful, and data exchange over the web became commmonplace, astronomers around the globe realized the potential for creating an online set of interconnected astronomical data and research tools that would ultimately offer the best "observatory" the world had ever seen. In 2001 the National Science Foundation awarded a large consortium of institutions an initial grant to create a framework that would eventually evolve into the Virtual Astronomical Observatory. Related virtual observatory efforts appeared around the world, especially in Europe and the UK.
The observatory's backbone was a semi-volunteer organization that created standards for all astronomical data to be entered into the database. The group was invisible to most practicing astronomers but critical for the virtual observatory's operations. For example, most astronomical images come in a FITS (Flexible Image Transport System) format. Virtual observatory standards put in place a decade ago allow astronomers to search, view, and exchange these images.
Today, in spite of funding woes worldwide and particularly in the U.S., the Virtual Observatory has created a set of free astronomical resources that are arguably more accessible and more coordinated than in any other field of science. But how can the public access those resources with an easy-to-use and powerful interface? Enter the WorldWide Telescope.