Please don't ask for people's Gmail and Yahoo passwords. While the marketing benefit might seem too good to resist, it really just teaches people how to be phished. Believe me, if the service is awesome, I'll tell my friends :D
I've already declined to give my email passwords to SlideShare, but it keeps asking for them and trying to email my friends. I've already said no, but every time I sign in SlideShare wants me to change my mind. Why won't my decision be respected?