They help avoid title collisions
This is precisely the meme I'm trying to kill.
When vanity tags were invented, the Monestary was missing a way to uniquely identify a node, and to help
sort out the author in the results of a search.
And the consensus that I recall at the time was
"OK, until these problems are fixed, vanity tags
are OK."
Both of these problems have now been fixed. We have [id://nnnn], or in brief, [nnnn] to handle the title collisions. And the search results now show authorship.
And thus now, it's time to end the vanity
tags. Let's stop it. Please.
-- Randal L. Schwartz, Perl hacker