Neocities just hosts web sites. It's up for the author of the site to write a page with <blink> (if they really want to), then for the browser that visitors use

Neocities just hosts web sites. It's up for the author of the site to write a page with <blink> (if they really want to), then for the browser that visitors use to visit that site to implement its functionality. The web host has nothing to do with it.