In the real world, wealth comes when each person produces more than they consume. In the online world, that becomes irrelevant. Things produced never go away, no matter how many times they are consumed. It’s a good thing that only 20% of internet users produce anything, because there is already more content supply than there is demand.

This is also driving shorter consumables. “TLDR” is a common forums acronym, which stands for “too long, didn’t read”. It’s debatable as to whether this is good for society or not, but the driver is for shorter consumables so there is time to consume more.

As long as real-world supplies keep on being produced so we can have our necessities (food, shelter, clothing, and internet connectivity), I’m not worried about the over-production of senseless videos, songs, blog posts, and memes. Besides, when considering the health of society, what’s the difference between LOLCats and The Simpsons? The Guild and 90210? People used to spend 40 hours a week on non-interactive 60-minute brain zombification broken into 10-minute chunks by 30-second blubs. Now they spend 40 hours a week doing basically the same thing… only this time, everyone has a chance to contribute now and then.

One thing that comes to mind contemplating what you say here is, if we assume that people after a ‘long day’ want to “waste time” and do that using social media instead of TV – the likelihood that they’ll be contributing something, a tweet, say, or a short comment, or a ‘lile’ or whatever can be done within a few seconds, is much higher than with TV, isn’t it?
So maybe we’d need to look a bit closer to what is meant by ‘making a contribution’. Maybe it’s the uncountable very small ones that, in the end, make a lot of difference?

For example, the person that follows a lot of people on twitter but doesn’t tweet much or the person that loves Wikipedia as a resource but never makes any edits, probably doesn’t feel any pressure to add something at the end of a hard day.