I am not a lawyer, but I am pretty sure it is illegal in the U.S. to publish the names (or details) of people and companies with bad debt. You are free to report them to collections, credit agencies etc, but publishing their names or other details is, I believe, a FCRA/FDCA violation. While generally applied to individuals, from what I understand it also protects corporations (but again, I am not a lawyer).
However, I would think publishing a list of businesses that you would not do business with again, like a black list of sorts wouldn't be illegal if you didn't say specifically why. Although I personally would not do this as the realities are it will make you look bad and potentially get you sued costing you money even though it likely would go no where.
FCRA = Fair Credit Reporting Act, FDCA = Fair Debt Collection Act.
The realities are that someone can sue you even with extremely poor legal arguments, however that lawsuit will cost you time and money. Someone who doesn't pay their debts won't likely sue you simply because you could then counter-sue them for the lost money (i.e. the debt). They also likely aren't in the same country/area as you so a lawsuit would be impractical.
The real "gotcha" is if you let other people put names on this list. As soon as you do that, you open yourself up to being sued for events and fights which you have no knowledge or involvement in. While there is legal protections for you publishing your own complaint, when you start publishing third party's complaints, you lose some of that...
I likely wouldn't, not because it will end badly, but just because it likely wouldn't be effective and would waste time/money. At worst I'd just publish a single google-accessible blog post with the info for a single incident (not other people's incidents/complaints).
Request: http://myblacklist.com/?firstname=Fffff&lastname=Llllll&comp...
Possible replies: {"status":"not found"}
{"status":"record found", "record_id":12345, "note":"Request more info at: retrieve-record@myblacklist.com"}
In "record found" case - allow requester to sign legal confidentiality and non-disclosure form before allowing to see more details.
This way no names are published open and you acquire a bit more of protection.
This is sort of becoming your own "credit bureau".
Talk to lawyers still about it.