Although, now I come to think of it, for years we did have default reading material, it was called a mass-market newspaper, and it wasn't all that bad. Newspapers are very readable and fairly sensible, content-wise, compared to something like reddit, because they're carefully designed by a small group of people to appeal to a broad cross-section, whereas the dynamics of social news sites tend to push shiny junk to the top.

A newspaper is like a default shopping cart which contains meat, vegetables, eggs, milk, bread, and rice. Not all of it is to everyone's taste, but if it arrived at my door every week I wouldn't die of malnutrition. Reddit is like a default shopping cart constructed by polling a thousand teenagers on their favourite foods; it contains twinkies, cognac, Junior Mints, bacon, Twizzlers and beer.