The crowd in Boston convinced me I should aggressively try to monetize my dormant domain names. I've already made arrangement to sit on the beach in Thailand while the money roles in:). The question is, what are general experiences with the various companies such as SEDO, AFTERNIC, etc? Or is it better to do it form scratch or set up my own system with something like Domain sponsor Pro?
The only rational way to explore the parking issue is to move your domains around and see which domain parking company works best for your domain collection. Try them all, if you qualify, and keep records. It's possible that some domain will produce better results with one company than the other so in the end you may have your collection spread across several.
Agree with what Webwork advises. It's quite a complex issue when you include all your domains. Let's simplify the choices by looking at 1 domain.
So, you have a domain. What to do with it? Develop a commercial website? Become an affiliate and earn income from referrals? Put up a 1-5 page minisite and earn income from Google Adsense? Monetize your dormant domain (park it)? As a rule of thumb, the more effort you put in the more income you will earn. These 4 options are ordered broadly by way of diminishing returns and efforts. Of course, there are always exceptions :)
You want to lie on a beach in Thailand, and choose to park your domain as the option of least effort. But wait! Don't pack your bags yet. You need to do as Webwork advised.
There are probably a 100 PPC providers of one kind or another. Select between the top 10, choose maybe 4-6. Park your domain with one of these. Select your parking page style and keywords. Keep it parked there for 2 months. Watch and record the data. You might want to change parking page style or keywords. That's another 1-2 months. Watch and record the data. Move it to another of your choices of PPC provider and repeat the process. There goes a year or more! Evaluate which PPC provider and parking page style and keywords provided the most income. Park it there and pack your bags. But wait, the 1st PPC provider you tried have just announced their next super-duper version which promises the best returns in the industry. Maybe you should try them again :)