All software downloads must adhere to Google’s Software Principles. Additionally, we only allow file downloads that can be "universally" opened, i.e. no special software is required to download the file, with an exception of (1) iTunes Store, (2) Flash plug-ins required to view page, and (3) PDF files provided that the ad clearly identifies the download as a PDF.
Ads and Brand Channel gadgets cannot trigger fee-based downloads without the user's prior consent to pay (e.g. mobile ringtone subscriptions), and may not contain links or interactions which directly initiate the download of a client application automatically. This includes plug-ins, browser helper objects, or other executable code that would run on a user's computer. If you would like to promote such a download via your ad or gadget, we recommend you use a click-URL to lead users to a landing page that allows them to initiate the download.
Additionally, if the user will be required to have specific software or programs to view or download the content, the specific program required should be identified.