[WikiEN-l] Why are URLs numbered?

[Steve Bennett]

Just wondering: when external url's are used in a page, why are they
numbered? That is, why is this:

[http://foo.com]

displayed as this:

[1]

?

I imagine that once this was a useful behaviour, before we had proper
referencing tools, so they kind of looked like footnotes. But there's
no list of these URLs generated anywhere, so what purpose does it
serve?

Would it perhaps be tidier to display something like a tiny [url] or
[link] or something?

Steve
PS I'm bringing this up on this list, rather than mediawiki or
wikitech, as it's a question of deciding what we actually want.