Why is there a * When There is Mention of Unix Throughout the Internet?

Most of these answers are far too late to the game, as the * usage was used on Usenet and elsewhere to refer to the multiplicity of Unixoid systems. This was significantly before "the suits" even knew what was happening in cyberspace and didn't understand it if they did.

I found a reference in the comp.risks archive dated May 1987 where the title

Concerning UN*X (in)security

was already so pedestrian as to warrant no explanation. By this time Xenix had been long on the market as were various "*ix" based variants which were decidedly "unix" but not "Unix".

To officially be called a "Unix", an OS has to adhere to the Single UNIX Specification put out by the Open Group. OSes that are similar to Unix without actually complying with the SUS are typically called "Unix-like", which is sometimes abbreviated as Un*x or *nix (since the OSes often have -ix or -nix suffixes: Linux, Minix, IRIX, etc.). Not specifically using "Unix" when referring to them also helps avoid trademark problems

Unix ® is registred as a trademark and was owned by several companies, such as

• AT&T
• Novell
• Univel
• Open Group
• SCO
• Caldera

Nobody likes to read documents like the 12-page trademark usage guide by the open group (pdf).

So the easiest way to refer to Unix was Un*x or *nix. The ® is not really necessary, but its simply a habit.