Normally I post with Private Proxies (YPP) and scrape with public. Today I did some comment posting on BlogEngine. I was posting (slow method w/decaptcher) and everything was failing. I then noticed I was running it with the public proxies I had scraped earlier that tested good. I had forgotten to switch it over. I switched over to the private proxies and had a 50% success rate, which is a whole lot better than zero. Just my unscientific observation on success with private vs public proxies.