If the toolbar is active, when IE is launched instead of taking the user to their homepage, they are redirected to an adware page for Yahoo mail.
It's an impressively aggressive tactic for cross selling, and some have expressed doubts that Yahoo themselves could be responsible for such a lapse of ethics and perhaps the toolbar has been compromised by malicious code.
Because the Yahoo toolbar is unusual in that it dynamically loads in content from the users Yahoo account when on start-up, a previously well behaved toolbar can suddenly 'turn'. As there is no apparent way to disable the advertising programme, users are simply forced to turn their toolbar off...
