Find a list of sites you are going to post to and use a unique code for each one.
As the signups come in you will be able to see which sites are sending them to you and which sites are not.
Drop the sites that are unproductive. Keep posting the the sites that work.
Use the extra time to trial new sites.
Again discard the useless ones.
Very soon you will be building a list of sites that you know will send you signups.
These sites may be different for whether you are promoting the TripleClicks listing, the SFI opportunity, or a product, so track EVERYTHING.
Also some results may surprise you so it's worth trying everything to see what works and then use the results to build a successful future campaign.