Instead of watching TV what if i browse reddit or HN and keep commenting? How is that any different? Sure I am not using my brain when watching tv but I am not

Instead of watching TV what if i browse reddit or HN and keep commenting? How is that any different? Sure I am not using my brain when watching tv but I am not really turning it off. I am still trying to process the visuals and in some cases trying to understand or predict what might happen. How different is that from mindless browsing?