My first guess would be backwards compatibility - the &quot;?=&quot; is easier to implement with old tooling, so maybe they changed their URL scheme at some point. But in that case they should have done one&#x2F;both of:<p>1) Only generate the ugly old-style URLs for the old posts.<p>2) Make the old-style URLs into redirects to the new ones, rather than duplicates. This way must be hell on the search engines.