FreshRSS, a free, self-hostable aggregator
After years on Google Reader, and then TT-RSS, and then basic python script I threw together, I've spent the last year or so on FreshRSS. It requires a DB, but sqlite works beautifully, making installation trivial. It's been very stable and provides a great "river of news" experience.
RSS in general acts as my "information nervous system", collecting up data from across the net and providing a way for me to filter, read, and share it with external tools. This site is powered by Shaarli, which is a bookmarking tool. What's cool is that FreshRSS can dispatch out to Shaarli directly, so as I'm reading through feeds, I can hit a button to share the link and my thoughts on it. Together, they are enough for a basic social network, since Shaarli sites also produce RSS feeds that can be consumed by others' RSS readers.
I'd like to see this more broadly adopted! If you're interested in democratizing social networks, it's a very nice approach that works right now.