From the webpage:
The International Aid Transparency Initiative (IATI) is a global transparency standard that makes information about aid spending easier to access, use and understand.
More precisely it is a standard for normalizing financial data in order to provide transparency.
Transparency is desired by donors of international aid so they can judge and control the use of the aid they donate. Non-transparency is desired by the recipients of international aid because they resent the paternalism of and interference in local affairs by donors.
I sense a lack of the common interest that would be required to make this standard truly effective.
Its code lists, on the other hand, could be quite valuable in creating mapping solutions between disparate information systems.
I first saw this standard mentioned in Using Graphs to Analyse Public Spending on International Development by James Hughes.