When you use free software, ads are usually part-and-parcel of the experience. However, typically developers are considerate enough to limit the advertising to within the app itself. Sadly, whoever programmed the popular document viewing application QuickOffice lacks such scruples and has decided to start pushing notifications to users, inviting them to upgrade to the paid version of their app. In many cases, QuickOffice is pre-installed with a phone's version of Android - even something carrier agnostic like the Nexus One - and is difficult to remove, leaving non-root users at the mercy of the app's creators.
Credit to TheFunkyMonk of reddit for the image
While the notification has only appeared once on people's phones so far, and is easy to dismiss, this really seems like an over-stepping of the bounds. Google themselves are masters at subtle advertising , but we can only see a method like this irritating users and turning them off the application or service in question.
We are reaching out to Google for a perspective on this, considering QuickOffice is such a widely installed application, and will update if we get a response.