The Guardian newspaper in the UK has today launched a free, open API which will carry all the content the newspaper produces in print and online, going back to 1999. The “Open Platform” will allow allow partners to reuse Guardian.co.uk content and data for free, in a clear move to extend the paper’s reach for its content and brand. But the payback for all this free content is that while apps developers can use the platform for “commercial” use, they are still going to end up building an ad network for The Guardian based on the API. It helps that the paper is owned and run by a charitable trust which does not have shareholders who would normally have a heart attack at giving away the family jewels.