> Why would they go public? Sorry, my bracketed "(ex-)employees" wasn't really clear enough. I was trying to suggest a vengeful motive after they had been fire

> Why would they go public? Sorry, my bracketed "(ex-)employees" wasn't really clear enough. I was trying to suggest a vengeful motive after they had been fired. > What is your basis for estimating the probability of such blackmail as "very likely"? Basic human nature. If you're directly employing people whose job is clearly unethical then you're painting yourself into a corner. Either they do in fact actively blackmail you or else you will feel unable to fire them in case they start telling people what you're up to - I'm regarding this implicit threat as passive blackmail here. I agree with you that there are lots of people who seem perfectly happy to do unethical or illegal things in order to make a living. They calculate (if not always very accurately) that the potential gains outweigh the potential costs. However, a lot of these people make such a decision in light of particular circumstances e.g. their low intelligence, or their lack of employability (due in part perhaps to an existing criminal record), or their unwillingness to work. Someone who has established a business that is making enough money to pay the bills should clearly be reaching a different conclusion to these sorts of people (at least most of the time). Their potential losses are much higher (i.e. loss of the business) and the potential gains are actually not all that favourable compared to doing things the "right way" - for example, by hiring a developer who can boost your business in other ways. > But even the business receives many positive reviews in a short period of time, that's not proof the reviews were fake. It's evidence. What a business owner might do if they suspected a competitor had hired someone to "opinion spam" is up to them. If they though a competitor was paying someone to post negative reviews of their own business then they could very well sue, and request access logs etc. from the review site in order to further the investigation. > Are there any such services which claim to be able to detect fake reviews? I haven't looked. But it would certainly be possible to create such a service without too much difficulty.