I forget how i stumbled on this entry on wikipedia about the web browser WorldWideWeb
It was written for the NeXTSTEP platform in 1990 on a NEXTcube and later renamed Nexus. I had never heard of it before, and it was the first ever web browser.
I remember NCSA Mosaic but this wasn’t made until 1993

But it doesn’t stop there, because this got me thinking…. does this mean the first person on the world wide web was using a NeXT Operating system?
I can see no way that this isn’t the case – and potentially this was the case for nearly 2 years as it was the only web browser on general release between 1990 and 1992. Am guessing the first person was the creator of the app, Sir Tim Berners-Lee who was the one to link the hypertext transfer protocol (HTTP) with TCP and DNS.

NCSA Mosaic was the first browser to run on windows and on an Apple Macintosh when it was released in 1993, though it was originally programmed for UNIX, ported to the commodore amiga and then to windows and the mac later in the year.
Perhaps the reason I had heard of NCSA Mosaic is because of this plaque:

I suppose what it is saying is that it was the first browser which ran on an operating system that home users would have. I don’t know how many people were running NeXTSTEP in the 1990’s, but I’m guessing it was less than either windows or even apple’s operating system (probably system 7 at the time)

I still find it a little bit misleading especially with the number of unix-like OS’s available these days

Just as an addon and to further back up the origins, this text can be found on wikipedia:

This NeXT workstation (a NeXTcube) was used by Tim Berners-Lee as the first Web server on the World Wide Web. Today, it is kept in Microcosm, the public museum at the Meyrin site of CERN, in the Canton of Geneva, Switzerland.
The document resting on the keyboard is a copy of “Information Management: A Proposal,” which was Berners-Lee’s original proposal for the World Wide Web.
The label on the cube itself has the following text: “This machine is a server. DO NOT POWER IT DOWN!!”
Just below the keyboard (not shown) is a label which reads: “At the end of the 80s, Tim Berners-Lee invented the World Wide Web using this Next computer as the first Web server.”
The book is probably “Enquire Within upon Everything”, which TBL describes on page one of his book Weaving the Web as “a musty old book of Victorian advice I noticed as a child in my parents’ house outside London”.
Photographed on August 10, 2005, by en:user:Coolcaesar.

Found this from this NeXT Computer forum at nextcomputers.org