Guest post by Martin Tisné, Director, Policy at Omidyar Network and Publish What You Fund board member.

I am very fortunate to have been involved with Publish What You Fund since its launch alongside the International Aid Transparency Initiative (IATI) in 2008, at the Accra High Level Forum on Aid Effectiveness.

That was five years ago. Publish What You Fund and IATI come a long way since then (literally, from being a desk in ONE to an organisation with its own US Advisory Committee) as has the open government movement.

Transparency is now seen as a key pillar of development – a necessary (but not sufficient) condition to enable growth, accountability and social change.

We have witnessed a ‘transparency revolution’. The basic principle that aid information should be publicly available in easy to use, accessible formats is now accepted as an essential component of international development – from the debates around the post-2015 Millennium Development Goals to the hundreds of commitments made by countries part of the Open Government Partnership.

Our agenda is now promoted by heads of state the world over. The recent G8 in Lough Erne exemplifies this. In 2011, the world’s most prominent development actors – including the U.S. – had committed to publishing their aid information to a common standard in the Busan Agreement. But in last month’s Lough Erne declaration, all G8 countries specifically committed to publishing to the International Aid Transparency Initiative (IATI) standard by 2015.

That means providers of over 90% of official development finance flows are now involved in IATI. That is a huge achievement.

The Lough Erne Declaration also recognised that while IATI lays the groundwork for open aid data, it provides a data standard that can be applied to other development flows. This is huge. Publish What You Fund has already worked to encourage three climate finance funds to implement, and they are currently preparing to publish to IATI.

The debate has moved on from ‘why aid transparency’ to ‘how aid transparency’ – moving from commitment to delivery. Donors should remember that making aid fully transparent is about more than just publishing information – it is about publishing aid information that is accessible, useful and used.

This principle of usability was recognised in the G8 Open Data Charter. The Charter was launched at the Lough Erne G8 Summit and committed G8 members to make data open by default and set out ways to improve its quality, quantity and – above all – its usability.

Turning transparency promises into reality is hard. Understanding how and why people use information is even harder. This will be a challenging task. It will mean working closely with dozens of diverse partners to ensure the huge amounts of information, which are going to be released can actually be meaningful. The culture is changing, open is becoming the default. With sustained political will, 2013 can be the year IATI data is scaled up and used widely.