Hi there, I just recently started SFI and as much as I am concerned, best way to become successful in SFI is to lead by an example. And that means that u will have to create a good SFI affiliate network to have people who will follow your good example. Therefore my answer is definitively sponsoring affiliates because they can also buy from TripleClicks but you benefit from them much more than from regular just TripleClick members.
