I've been in a few niche online forums and chat rooms that specifically forbid their members from discussing anything about the rates they offer as contractors. Some claim it's price fixing and outright illegal, others that it's too gray of an area they just don't want to be anywhere near.
I can see where they're coming from: various descriptions of price fixing I can find on google seem to use broad strokes, suggesting any coordination intended to affect market value of a service amounts to the crime. But then I also see professionals talking about it on bigger social media platforms like Twitter, encouraging their peers to price themselves higher (apparently it's common for newer software contractors in particular to undervalue their services and underestimate their costs). These comments, often turning into extended conversations mentioning specific numbers, don't seem to have any problems.
Where between explicit market manipulation and well-meaning mentorship is the line drawn?