I started using Afternic parking, because I got it free with the Discount Domain Club. The payouts seem to be on par with other companies at first, but rapidly fall to 0 or close to it. The fact that it takes 2 days to see your stats makes this service much harder to use and less usefull than others. You can't tell if changes make any difference until a long time later. Also, the visitor stats seem to be anywhere from 5%-20% of the visitors shown from at places, so I am not using them anymore. Godaddy does not tell you immediately when a purchased domain enters your account, so, if you are already paying for Afternic parking, it does make sense to have them automatically pushed into your Afternic parking account as soon as they enter your GoDaddy account. I usually point them somewhere else before they make any real money(and can't see how they did until days later anyway), but if you don't point them towards Afternic automatically, then TDNam will put parking ads on it anyway and until you point it somewhere else, will not pay you for it, since you have not told them to park it or forword it elsewhere.
I hope this helps.