Satanism (Satan-ism) is an atheist religion created in 1966 by Anton Szander LaVey. It is distinguished from devil worship in that Satanists do not worship Satan or any make believe spiritual beings. We only worship ourselves, life, and perhaps certain individuals who are worthy. Satanists do not believe in God the devil or a spiritual world. We believe that life begins and ends here in this world. There is no other. Satanists use the lunar or "inverted" pentagram and sometimes the goat as symbol(s) of the physical carnal world we inhabit, this is opposed to solar pentagram which represents the pretend "spiritual world" and or fantasyland. It is of special importance to note that the solar pentagram once was the symbol of Christianity which we Satanists strongly oppose because of the physical and psychological damage that religion has done to world. It is for this reason that we take on the mantle of the adversary of Christianity, Satan, who is our mascot. This does not mean that we worship Satan anymore than the Chicago Bulls worship a giant red bull.
Satanists are law abiding people who don't harm children or animals or even other adults (except in self defense if no other option is granted)
Satanists don't waste time on fools or ingrates, life is too short
Satanists use "dark" imagery not because it's "cool" or that we worship evil or death but because such is the nature of the representation of the Prince of Darkness
Satanists, again for the record, do not worship death or evil, or Satan or any of the many pagan or Biblical "gods".
All Satanists are atheists but not all atheists are Satanists.
Satanists follow the 11 Rules of the Earth and 9 Satanic Statements. The essence of which has just been communicated to you For more information on the particulars or on Satanism in general see the official Church of Satan website at www.churchofsatan.com or ask me about it in the comments section below.