What is Hellenismos?
Hellenismos is the modern interpretation and exploration of the ancient Hellenic religion as it has come down to us through their history, philosophy, and mythology. As one of the foundations of Western Civilization, the Hellenic peoples are among the most understood of the ancient cultures of the Mediterranean, and their religion has received its share of study. But the suppression of much information by the Church during its own foundation, as well as destruction of ancient sites, sanctuaries, and documents of religious importance by the same Church and the many wars that have ravaged Greece over the Millennia have left us with serious gaps in our knowledge of Hellenic religious thought and practice.
Modern Hellenismos, then, is not a direct continuation of those traditions, as the Church did a good job of eradicating the religion in ancient times, but an interpretation and amalgamation of religious philosophy and practice based on the knowledge we do have of their religion.
Modern Greeks in many areas of Greece, however, claim that many practices and folk beliefs did indeed survive into modern times, including a belief in certain nature spirits that were once commonplace, but which are now mostly considered superstition by the Orthodox Church and its still active suppressions of any religion not their own.
Hellenismos, as a rule, is not strictly what a lot of people would consider "neo-pagan". Unlike Witchery, Wicca, or other such religious paths, Hellenismos itself does not focus on magic, nor is it what one my call "Earth Based", which is in many ways like saying "hippie". But is does hold a lot of things in common with all of these, especially some of the more tradition based paths, like Khemeticism and Asatru. It is based on a system of beliefs stemming from the belief in many Gods, and that colors this religion more than almost anything.
Like Asatru, Khemeticism, and Celtic Traditional Religion, Hellenismos is based squarely in the social, religious, linguistic, and cultural traditions of a people, and yet it is not limited to them, because the ancient Greeks were often willing to accept foreigners into their religious practices, and sometimes accept their Gods into their cities and culture.
Thus, Helllenismos is the religion of the ancient Greeks as seen by modern people from all over the world.
To me, however, and I speak only for myself here, Hellenismos is the acceptance of the aspects of the Gods as seen by the ancient Hellenic people and their influence. It is not simply mining the Greek religious sphere for whatever I find convenient and merging it with everything else I think is cool, but an actual acceptance of these Gods as manifest and real, and that within the context of this religion, there is a divine truth to be discovered and made a part of myself.