In the literature world there are levels of writing and levels of reputability; for example a magazine article is different from an essay or a short story. I've been thinking about how there is a similar hierarchy online. Maybe blog posts tend to be more reputable than Facebook updates, which are higher quality than Twitter tweets.
And I'm not just saying this because my father blogs and mother-in-law uses Facebook, a researcher recently found, in a pilot study, that Facebook increases your IQ while Twitter probably weakens your working memory.
Perhaps all reading is not good reading.