Thinking back to the traditional-style adware that came bundled with 'free' software on Windows, and how it so often lied about its purpose.
And pondering how things would have gone if they'd just been honest about what it was - "we ask you to install this software that generates X ad popups per day, and it pays for our software development".
I know that Zango did this for some time, with reasonable success.
(Oh, and the popups were clearly labelled as originating from them)