Just like no single person could ever find the time to watch every movie or TV show released (let alone all the video on YouTube); you can't possibly 'keep up' by reading everything.

When I am in learning mode, I try to mix up a 'breadth first' approach with an occasional 'depth first' method.

Pick up enough tidbits of information about a few popular topics so you can have a half-way intelligent conversation about them. Dive into detail on just a few of them so you know more than the average person about those.

Don't worry that you can't do either of these approaches for every single topic possible.