That's a tricky one if you're saying you want to have a list—don't go here or you could be at risk here—because it shifts over time and the problem is that platforms can be used by anybody. To single one out because there may be a presence of some nefarious activity there, that could be detrimental to others who use the same platform when it's in fact not used solely for that. There are encrypted messaging apps that exist that we use to communicate with one another because we trust them more, to be quite frank, sometimes, and that the public uses and that bad people use.
It's kind of a difficult thing to draw a line and say this bad and this good. As well, this sort of issue does shift over time.