Neocities is basically a revival of Geocities.
In the early days of the internet there was a website called Geocities that allowed you to create your own website for free!
It operated from November 1994 until October 2009 in the United States, and in Japan, until March 2019.
Before shutting down, there was a project by the Internet Archive to recover and archive the user-generated websites made on Geocities, as it was an important piece of Internet History.
The Internet Archive also released a project called GifCities, which preserve .GIF images archived from GeoCities, which some of the images on this site use.
And that is the basics of what Neocities is. You'll find unique sites and identities that you just cannot find on Social Media.