You don't want confuse lead nurturing with sending out brochures or marketing copy focused on your product information or your company announcements. This is not the same thing as nurturing a lead.
To nurture means: foster, help develop or help grow; the act of nourishing or nursing; tender care; education; training; that which nourishes; food; diet; sustenance; the environmental influences the contribute to the development of an individual.
Sending out information about you or your company is not the same thing as feeding your leads. When you talk about yourself, you are not focused on what the leads need or your relationship with them.