Can't really think of anyone, but statistically speaking, since there's free speech there should be a lot of hate speech. I'm not sure about other's, but here on hive there's little to non.
When web 3.0 goes mainstream there may be a bit more, if measures are not created to limit it. Besides, there's already lot of hate speech on web 2.
Other than that, I can't really think of any disadvantage. More may surface in the future though, you know how humans are.
!PIZZA
RE: What is Web 3.0?