Internet is ridiculously overwhelming, I wish I had the time to read every article that I find interesting, but the reality is that internet makes available so much content of quality out there that it's impossible read everything, even if your interests are relatively narrow.
Stumbleupon was (maybe is? I haven't used it in ages) a useful tool to get to places on the internet one wouldn't usually go to. The internet is supposed to be a vast limitless mess, it's like a terrain made of ideas, and it's our job to go exploring.
