title: How to build a private "Google Apps Marketplace" apps for gmail intergration like Rapportive does
body: <p>Google Apps Marketplace (<a href="http://www.google.com/enterprise/marketplace/" rel="nofollow noreferrer">http://www.google.com/enterprise/marketplace/</a>) has enabled contextual gadgets so I could integrate my functionality in gmail. I would like to do so but I don't want to publish the app. Is this possible? (<a href="http://developer.googleapps.com/marketplace/getting-started" rel="nofollow noreferrer">http://developer.googleapps.com/marketplace/getting-started</a> tells me I have to become a vendor.) If I can do so I can't find any example code how to integrate in gmail, e.x. access a message, add a button, ... BTW: Greasemonkey is NOT an option.</p>