A website is useful because you could redirect it first to some wikipedia site so it looks like a legitimate source but once the parasite starts ranking you could redirect to your aff link OR host your own landing page on it, some think their LP's convert better so they use it instead of the original one of the product. Also, you could use the site as squeeze page to capture the email before letting the user through to the product.
Third reason I could think of, what if the product suddenly stops selling? You can't redirect an affiliate link.
BTW:To answer your question: Last time I tried redirecting a blogger it worked perfectly fine. Just find the basic redirect code for html and put it in the head of the page.
To the guy who claims parasites can't be ranked, why would people use parasites then? Ranking for good keywords is still possible with parasites, but you can think otherwise. Less competition for me!
My 2 cents