Social media is undoubtedly a democratising force, allowing equality of access to those who want to have their say, whether that be about the quality of food in a restaurant, Scottish independence, or encouraging world leaders and celebrities to undertake a charity challenge.

But online anonymity can seriously undermine those democratic benefits. When comments are posted by people who hide behind a pseudonym it can lead to upsetting and offensive 'trolling', such as the appalling and horrifying abuse of Caroline Criado-Perez and MP Stella Creasey who campaigned for more famous women to feature on banknotes.

It can enable cyberbullying of young people, or allow apparently defamatory statements to be circulated without any comeback.

In the case of review sites like TripAdvisor, it calls into question the motives of those posting a review of an hotel or other venue. Just as authors have been found secretly reviewing their own books positively on Amazon (or doing down those of their rivals), some hoteliers fear the system permits potentially highly damaging opinions to be published without sufficient safeguards.

That is the position Martin and Jacqui Clark, of Kinlochleven, found themselves in when unfavourable reviews about their guest house appeared on the site. Convinced the comments were malicious and the events described fabricated, they sought to sue the authors for defamation.

However the Massachusetts-based company refused to reveal their identities. The Court of Session refused to order the firm to reveal those behind the posts earlier this year and that decision has now been upheld at appeal.

Other proprietors have had problems with the site. In February, Callander hotelier Alex Scrivenor managed to turn it to his advantage after responding with vigour to the opinions of a troublesome guest and seeing bookings rise. But he has still been subjected to further unverifiable reviews which he believes are from people who have never been guests.;

It cannot be right that anonymous reviewers can do untold damage to the reputation and business of a company or trader without any accountability at all.

Newspapers like the Herald publish reviews of all manner of events, venues, products and destinations regularly but in a transparent way, abiding by the law. But online reviewers may not. This is not the first time a major internet company has been slow or resistant to taking the right course when its systems are used in apparently abusive ways. Facebook and Twitter have also faced such criticisms.

It is worth noting that American companies were not slow to take advantage of British libel laws to sue critics, before the rules were tightened to make this less attractive.

So it is most unattractive to see TripAdvisor hiding behind Massachusetts law in defending the right of its users to write anything they like.

The bad reviews of the Clark's Highland guest house may not have been malicious. They may have been justified. Or they may have been unbalanced but made in good faith. We cannot know. For all its popularity, until the problems of anonymity are addressed, TripAdvisor and all similar operations cannot be trusted or their reviews relied upon.