1 of 5Image
Left: This means that data is only collected and used to carry out the interaction you are engaged in with the website. The website is only using your data in ways that are functionally necessary to carry out the relationship as users intend.
Right: This means that your data is collected and used in ways that go beyond what is necessary for the interaction, like selling on to spammers and junk mailers.
Source: Aza Raskin's blog
To read more about Privacy Icons, head on over to the ZDNet iGeneration blog.