A free, self-hostable news aggregator…
WebSub/PubSubHubbub for WordPress
FeedOnFeeds is a lightweight server-based RSS feed aggregator and reader
Support WebSub and Webmention on a static site
A WebSub Hub implementation in Node.js
a WebSub / PubSubHubbub 0.4 hub
A powerful micro/blogging engine with IndieWeb features (abandoned)