It seems likely to me that a lot of the content on the Web is nearly identical: blog posts often say similar things to other blog posts on the same topic. These blog posts are written, often not by the blog's owner, to collect advertising revenue. What does that tell us about the content?
With so many blog posts being so similar, that is, saying the same things about the same things, we can imagine them as songs played on a radio. The Internet Surfer is fed or otherwise comes across these postings, and so “hears the song.” With a blog post, it's unlikely the person will reread the post the way so many people like to hear certain songs again and again. Blog posts are disposable; we consume the post and never read it again.
Memory for news, events, memes, blog posts, can be expected to decrease as exposure to these media items increases; being able to remember only so much, more text, sounds, and images leads to a lower absolute number of these items being remembered. Our Surfer may remember an exemplar of a type of media item. A particularly popular Star Wars meme, or a blog post that said something just so, may function as the memory handle on a whole slough of similar and possibly inferior items.
Each type of media item is like the song on the radio: you've seen one of the type, and you've seen them all. Seeing one of a type is hearing the song again. As we scan the Web, “turning the dial,” we hear the same song many times. Songs come into and fall out of favor rapidly, and we may forget we've even heard the song.
I use the radio analogy not only because it struck me first; the radio is entertainment used to collect advertising revenue. The Web is entirely entertainment: news, activism, shopping, Internet radio and streaming video – all are entertainment. “What about online education! What about moocs?” I am impatient at having to say it again: the entire Web is entertainment. What is not entertainment is not the Web; it is something else for which I have no name.
A final note: when thinking of blog posts as songs, we formed a schema of the song from the different, similar blog posts. Future radio may be used (to collect advertising revenue) to broadcast or to stream songs that have been altered by a computer, in such a way that no two plays are identical. In the first case, “out of many, one”; in the second, from one, many.