This may be the 30,000-foot view, but I think Wikipedia does the most damage to society by creating the illusion that "regular people" can be responsible for credible, reliable stores of knowledge. Personally, I believe that average folks can do an amazing job pulling together bits and shards of information, but that does not equal "knowledge". True knowledge demands the ability to discern not only truth from deception, but also to glean what's important from the ephemeral. This skill takes time, experience, and training to properly hone -- something 98% of Wikipedians couldn't care less about.
So, we are gradually seeing newspapers and print encyclopedias going bankrupt around us. They, ironically, happen to be the lifeline of "reliable sourcing" for Wikipedia itself. So, what happens when Wikipedia has driven them all out of business, because too many people have swallowed the myth that Wikipedia does a "better job" of reporting information? I suppose at that point, Wikipedians will create a new rule allowing editors to simply report as fact the things they see in the world around them, and at that point, Wikipedia will be an electronic form of sensory vomit.
There's a reason the phrase "You get what you pay for" has been true for centuries.