Reverend Rick you name-dropper you
Ok, I'll post a few of my own thoughts on the topic which may or may not coincide with the views of other Pagans, Satanists and folks in between, so prepare yourselves for a bit of an essay.
Firstly it's worth mentioning that possibly the most common variation of Satanism is atheistic/autotheistic Satanism. To give folks a very brief rundown, these folks don't believe in a literal Satan, but they do view him as both a potent symbol and a worthy figure to emulate. You'd be hard pressed to call this type of Satanist "Pagan" without using an incredibly outdated definition of the word.
Now theistic Satanists will only very rarely believe in and worship a malevolent Biblical demi-god. Those that do, usually tend to be your stereotypical rebellious teens who go into it for shock value or because they feel alienated by a primarily Christian society. Some of these will go on to either theistic or atheistic Satanism of a more mature variety as they get older and begin to calm down, some will abandon Satanism entirely and a few will stay that way long into adulthood.
I would suggest that this particular form of Satanism is the closest you get to what some call "inverted Christianity" and could possibly be considered Abrahamic as Draka mentioned as it often draws largely upon Christian ideas of Satan. I would suggest though that it tends to also draw on heavy metal imagery as much as, if not more than, Christian ideas about evil.
Some theistic Satanists have a single deity that they refer to as Satan, though I imagine these are actually a minority among theistic Satanists. With the exception of those I mentioned previously, the Satan these folks worship has little in common with the Biblical deity or is at least viewed more in terms of his positive attributes (encouraging freedom, self awareness, earthly pleasure etc).
In my experience, most theistic Satanists appear to be polytheistic or henotheistic. Satan may or may not be the head of the pantheon, but other gods/demons are also invoked. Demonolatry largely falls into this category and is in my opinion, the halfway point between Satanism and Neo-Paganism. Some Demonolaters lean more towards Satanist and some more towards Pagan. Whether we call ourselves Pagan, Satanist or Demonolater seems to be largely down to personal taste and mood.
Considering Demonolatry and many forms of theistic Satanism are polytheistic it seems that some definitions of "Pagan" fit quite well. Of course if we take Pagan to mean "nature based religion" it rules some Satanists out, but by no means all and if we take a reconstructionist view of "Pagan" it again rules some Satanists out, but by no means all.
So I would say that no, Paganism isn't Satanism and Satanism isn't always Paganism, but there is a definite crossover point with regards to certain branches of theistic Satanism. Of course I should probably point out that neither Pagans nor Satanists are particularly fond of sacrificing babies
Anyhoo, just to cover your post here Draka:
He's free to correct me if I am wrong, but the concept of beings known as demons is not exclusive to Christianity so claiming anything to do with demons does not specifically mean one is not a Pagan of some sort. As to his title, "Devil's Advocate" means one that will argue from an opposing side just to point out other sides of an argument or to show a weakness in said argument. It doesn't necessarily really mean "advocating for the devil". If he really meant it literally then I welcome him correcting me.
You're right to say that Demons aren't solely Christian and I've yet to encounter a Demonolater who views them as malevolent fallen angels. In fact if you look up the etymology of the word "Demon" you'll encounter the phrases "Divine Power", "Guiding Spirit" and "Intelligent Being" among the historical definitions of the word. It's true that many Demonolaters are also Satanists and that many of the demonic names we use are straight out of the lesser key of Solomon. The reasons for this vary between practitioners and as I mentioned earlier, some lean more towards Satanist/Pagan than others.
Personally I probably fall closer to Pagan, though I'm willing to use Satan and Devil in my vocabulary depending on my mood and intent. I also view the names of deities as being archetypal rather than fixed, so I'm equally happy invoking Asmodeus as I am invoking Aphrodite. Like I say, I fall somewhere in a grey area between Satanist and Pagan.
"Devil's Advocate" is a bit of a pun since I fall under both the meanings you mentioned. I'll happily take part in a debate I have no real passion about just to hone my debating skills and yet I also support "The Devil". Not the fallen angel of Christian Mythology mind you, but the mass of cultural fears, taboos and repressed desires that I see as our modern day Satan.
To be honest I could write pages on this topic, so if anybody's unsure of anything I've said feel free to ask and I'd be more than happy to clarify
