Cloaking for FB members

it's more and more difficult to cloak based on agent's IP and footprints, but how about cloaking affiliate links by using FB?

I.e. search bots and normal traffic will be sent to a normal link. Ok, no money from them, but benefits for seo. for people who are logged in FB or Twitter account, normal links will be replaced by affliliate links. Would that be possible to do? Any ideas?

That looks pretty hard to do it

It's very easy to do actually, and we do it for a long time now. We use this technique for clickjacking, i.e. identifying if a user is logged in to FB or Twitter before presenting the hidden LIKE button, but, it can easily be done to present different links, HTML content for different users.

would like more insights about this?
how can this benefit my campaigns?