How you can do it "unwittingly"? If you put a button on your site that says "like us on Facebook" or "analytics by Facebook", how can't you realize you're invit

How you can do it "unwittingly"? If you put a button on your site that says "like us on Facebook" or "analytics by Facebook", how can't you realize you're inviting Facebook into your relationship with your site's visitors, and you do it completely voluntary, expecting to gain more exposure, better marketing tools, etc. ?