Pornography isn't even close to what it was 30 years ago when you for the most part only saw it in nudie mags that your dad had (or friend had who stole it from his dad). Today, kids have easy access to a wealth of horrifying and bastardized hard-core pornography.
But not only that, the ads and search results and images that show up for the more innocent things will lead them to the more awful things, because they're just readily visible and accessible right there.
To be honest the only solution we have found is twofold: to change our wifi password to disable internet on all devices (he was sneaking his Nintendo 3DS into the bathroom for 2 months to look at porn on it) and to proactively start teaching them that life is more than a constant quest for more and more intense pleasure, and that if you allow yourself to give into that base mentality, you are throwing away a good portion of your future that could be filled with meaningful real relationships and legitimately joyful times, in exchange for maximizing pleasure and minimizing pain until you die.