u/Alternative_Winter82

I've been reading fanfics on AO3 for years, but recently I've been encountering links for AO3 stories that don't link to their main site. Sites like archiveoftransformativeworks.org archive.gay and archiveofourown.net I found a bare mention of these "mirror sites" by Googling, but I still don't understand their purpose or if they are safe to interact with. Can anyone explain it to me?

Thanks!