To be sure, many Satanists use the Internet, some quite often. The Internet is a great tool, after all. Random Stranger, for example, pointed out that it's great for those with limited mobility in some way.
But, I define an "Internet Satanist" as someone who puffs themselves up online, but is basically just another "role player" who is using the medium to create an elaborate, but ultimately fake, persona, and indulge in delusions of grandeur.
Anyone can make a webpage and declare himself the High Priest of his own made-up Satanic church. Likewise, anyone can lie about his accomplishments or exaggerate about his assets, while spending his whole life eating Cheetos while watching daytime soaps at his mom's house. The online talk doesn't even remotely match the real-world action, basically.
"Gentlemen, the verdict is guilty, on all ten counts of first-degree stupidity. The penalty phase will now begin."--Divine, "Pink Flamingos."
"The strong rule the weak, and the cunning rule over all." HS!