Awesome feature for the URL filtering, although I’m finding that it doesn’t appear to apply to articles in the iOS app.
I use it for site feeds which cannot filter on their own categories, and do not have tags. I set a ‘dislike’ for the publisher so all articles are hidden as standard, and then set a ‘like’ for the desired category path in the URL, so only those articles are shown in Newsblur. Works perfectly in the web. On iOS, the feed list shows an unread article, but clicking into the feed shows zero articles.