I've been pointed to harvester when I was looking for a non-Python aggregator, and while getting ready to use it I've made a few changes to fix its behaviour and implement the zlib encoding (as one of the feeds I need to aggregate is provided always gzip-encoded even when it's not supposed to be available).
Don't consider <core> akin to <pre>.
While not commonly known, <code> is an _inline_ element, and is used
that way in most technical blogs.
fetch: make sure to use the string and not the DateTime object.
When using DateTime with PostgreSQL 9.1, it complains about sub-second
fetch: implement zlib decoding of content.