Imagine a task (actually, quite common), if you have:
- a nodes (articles, ads, whatever) taxonomy in Drupal,
- a taxonomy-based url path rewrites, like /monkeys/primates/homosapiens
- and want to show a block/page View with articles only from current path term (and, maybe, its subterms).
It might be a hard time finding out the current term. One could try having two nested views, passing a current term as a parameter to nested view, like Dustin Currie did.
Though, Views has several pre-defined solutions. Just go to /admin/build/views/ and enable this one: “Default Node view: taxonomy_term”, (clone it to play safe), voila!
You got a View for the current term.