"Hello, I am the product creator. Here's the sales page for my new product, The Whizzbanger 3000! You'll see on the sales page lots of *BUILT-IN* bonuses."
Then, the emails start coming in...
"Hello I am Joe Affiliate. Y'gotta see that new product called The Whizzbanger 3000! --- And don't forget, buy now and you'll get all of (((sometimes they actually use the word "MY" and sometimes they don't, but the "MY" is always strongly IMPLIED))) my/these BONUSES!!! Yippee!!"
In other words, the affiliate is basically implying that the BUILT-IN bonuses, are HIS bonuses -- when the REALITY is, EVERYONE GETS THOSE BONUSES, no matter who they buy from.
I think this "strategy" is a little misleading. Also, it allows them to use the word "BONUSES" in their email, so when people are trying to decide whose bonuses to buy with, and they do an email search for "Whizzbanger 3000 +bonus" all the affiliate's emails will still show up in search.