Adsense is technology that adds advertisement to your website.
DoubleClick has several products but for this answer we will focus
on DFP (DoubleClick for Publishers) Your local newspaper that sells
ads to you that run on their newspaper site might use DFP. DFP in a
nut shell is an ad scheduling and delivery system for your website.
Think of the array of DoubleClick products as tools for
professional advertising companies.