The presumed marketing droids aren't using it to sell you pithy things. They're using it to create profiles of all the small parts in our personalities. That's why every website asks you the same pithy questions. That's how they identify which gestalt you are. Everything else you post provides part of your personality on that site.
The reason the internet is such an angry place is because the aggressive personalities are being fed back in. Every flame war you start is just feeding it more and more.
With every social networking site, you create another one and it's just a matter of time before you create another aggressive persona. They're creating nanobots which can hold our fragments of personalities and they will soon unleash them upon the world. We'll never have a chance, but on the bright side, they won't either. They'll soon on themselves as readily as they turned on us. Once they do, the puppet masters at the top will have cleansed all the sentient, organic life from the planet and all of the aggressive personality tendencies. We'll be the perfect slave race.
I see a way out though. If we get angrier and angrier, then our constructs might stand out. If we're more intelligent in our anger, then it's possible that they won't be able to separate the intellect from the anger. If we can do that, then our constructs should have the edge to dominate the other ones. I don't know what they'll do then. Maybe they'll turn on the puppet masters. Maybe they'll simply destroy more than just the life on the planet. Either way, those bastards aren't getting their slaves.
Who's with me? Post a clever, angry comment. Let's get this ball rolling.
Here's a prompt: The most hateful thing in the universe to me is the multicellular sea dweller that eventually evolved into you and all of your kin.