MediaWiki talk:Welcome-user

Would be funny if this was marked as a stub, further up my curve of education I guess. What does it do, or what it it used for? My reasons for asking are;, I'm curious (okay, nosy too, but I won't look in your diary), it can be edited but is MediaWiki for admin/all/other? I feel very dumb :( I'll get over it :| I'm over it :)