Riding on top of `#689 </issues/689>`_, it took me a while to
figure out that Markdown could be used (after HTML and Textile, I
ended up figuring it out from looking at closed issues). I don't
have any particular suggestion, but maybe an info box on the side
or the footer could indicate what can be used to format their
text.

(this is to discuss this and then possibly implement it.
Implementing is **very** easy).

Currently jinja2 replaces ``{{ not_known }}`` by the empty string.
The question is, wether it would be better for it to throw an
error? Rationale being: Either it's a typo, or it's an error for
the variable to be referenced but not being there.

Does that make sense?

Enabling this:

::

    mediagoblin/tools/template.py:
    @@ -43,6 +43,7 @@ def get_jinja_env(template_loader, locale):
    
         template_env = jinja2.Environment(
             loader=template_loader, autoescape=True,
    +        undefined=jinja2.StrictUndefined,
             extensions=['jinja2.ext.i18n', 'jinja2.ext.autoescape'])

The changes in Issue `#582 </issues/582>`_ introduced some
interesting code:

::

    def user_may_delete_media(controller):
    ...
            uploader = request.db.MediaEntry.find_one(
                {'slug': request.matchdict['media']}).get_uploader()

If two people have the same slug, this query will not always do the
right thing(TM).

That said, I'd really prefer things like "edit" and "delete" use
the id instead of the slug. It just feels safer and will avoid all
these slug duplicates/etc issuess.
I don't see anyone needing to bookmark the delete page? And
bookmarking the edit page might have rare use cases, so those
should be able to live with ugly urls.

For performance/safety reasons, we could consider to have an extra
decorator for finding the media only by user/id or somesuch.