Our link directories are all developed through direct communication. Human to human. When Zeus and the other robots came on the scene, we considered the possibilities and decided that, while the resulting links promised more hits for our site, they were also indifferent, bland and lacked a human touch.
Therefore, we opted to continue to search for quality websites, with our own hearts and eyes. Trying to provide our visitors the best possible information. In keeping with that, we do not link to sites with directories that are maintained by automated software, like Zeus.
We do have one or two links to robot directories. But, these connections were made in the early days of linking robots, and we maintain those connections because A) the websites are of value, and B) we agreed to create the links and we keep our word.