When lists of articles on a category page becomes huge,
it will become difficult to browse through all the
articles. When the list size exceeds some threshold,
it would be nice to change the display format:
split article list up by first letter (as listed in
piped key) within the page, autogenerate a TOC.
As above, but include only one first letter per page,
with the first page including ONLY the TOC. Within
each lettered page, split the page up for the first two
letters if there are enough entries.
(The TOC could be static rather than generated, and
just always include every letter.)