Yes! Zango is a horrible thing to install - don't install it
I don't remember what exactly it did, but I remember I hated it.
Here's some info about it from Wikipedia:
StopBadware.org lists a number of undesirable behaviors associated with Zango Easy Messenger, including "behaves as spyware", "automatically runs on startup", "displays pop-up advertisements", "installs adware", and "bundled software cannot be closed". The same site states, "We find that Zango Easy Messenger is not badware, although it does engage in behaviors that users should be aware of."[6]
Websense issued a Zango-related security advisory in November 2006. The report stated that "Websense Security Labs has discovered a number of user pages on the MySpace domain which have videos that look like they are from YouTube. The videos have an installer embedded within them for the Zango Cash Toolbar. When users click on the video, they are directed to a copy of the video, which is hosted on server sites such as Yootube.info, Yuotube.com, Youtuhe.com, and etc. these all will most likely give you spyware."[7]
A more detailed analysis of this attack appears in "Zango Practices Violating Zango's Recent Settlement with the FTC": "Zango continues numerous practices likely to confuse, deceive, or otherwise harm typical users as well as practices specifically contrary to Zango's obligations under its November 2006 settlement with the FTC." These include failure to include on-screen disclosure of material terms, widespread in-toolbar ads without labeling and hyperlinks, ads for "bogus sites that attempt to defraud users", and third party installations without disclosure.
Automated analysis by McAfee SiteAdvisor in May 2008 reports "629 red downloads — In our tests, we found downloads on this site that some people consider adware, spyware or other potentially unwanted programs." [8].