1. Quality newsletters - they help you know what's important and aggregate commentary around it. My favorites - Mattermark's Daily Digest, Pocket hits, JS Daily/Weekly, Quartz Daily Bried
2. BUZZSUMO (paid but worth it) - helps you sort through the noise and see share volumes for each channel based on a domain (ex. wired.com) or you can set topics where it aggregates most trending pieces based on virality of shares. Also has content analysis tool that allows you to see what keywords are most common for a domain and analyze FB page content for shares and popularity. Does much more but that's the quick and dirty.
3. Of course HackerNews is great, especially if you cater your content to a techie audience.
4. Twitter Lists + Nuzzel