They used to do that, they got in trouble with the FTC because affiliates were bundling the software and not running the TOS upon installation. What Zango actually is, is adware. Advertisers buy keywords and urls from Zango and is displays pop-overs based on what who bids the most money.
Spyware, whoop-de-fucking-do. What do you think Alexa toolbar does? Or Google's? All *spyware*, they record data and send it back to the companies servers. Google even admits that it will keep personal user data at least 14 months, if not longer. As for spyware that steals your passwords and credit card information, thats a whole different category -- which Zango certainly is not, nor is Google or Alexa.