None of that is new either, is it?
I think the problem is a human problem and it has a lot more to do with the democratization that the web has experienced than it does the medium.
Think of just writing itself. Writing was once something that only a handful of people could do. This greatly limited not only the number of opinions that could be composed, but also how many people those opinions could reach. As writing became more ubiquitous (both the number of readers and writers increased) the number of writers that could project their writing to a broad audience remained fairly low whereas literacy reached further and further. If looking back we see behind the wall of "limited access to writing distribution" significantly better quality in writing, this most likely has to do with the selection process acting on writing itself. Someone controlled what writing was distributed and they controlled who did the writing.
As the barriers to writing and distributing even out (that is, distributing is no longer a factor, and nearly everyone has been able to read for quite some time) there is no longer any gate keeping, and there is no longer any selection process. Now, instead of those processes dictating what comes into existence, we have democratized systems for searching and filtering through the mass of content that can be created and distributed by anyone. So instead of a selection of well informed editors deciding what the masses will read, we have the masses selecting for themselves using tools that don't have a content and don't have a mission statement; they're tools designed to give the person what they want, regardless of what that is.
That said, the intelligent can still filter out the crap, it's just that when they do so it is a personal filtering; they no longer get to dictate to the masses what it is that they are permitted to read.
I think there are positives and negatives in that, but overall there are probably more positives.