Some years ago I took my dad with me to the theatre. There were interval drinks for critics and guests in a small room. My father walked in among the assembled critics and asked loudly: "So are we all enjoying it, then?" Everyone froze as if he had just lobbed a hand grenade into the room.

There is an unwritten rule (at least I don't think it's written down anywhere, but it may exist in spidery writing on crumbling parchment somewhere in the dusty vaults of the Critic's Circle) that reviewers never discuss the play they are watching with each other. The idea is that we should not have our own views infected by each other's opinions.

But if you spend enough time in theatres with the same group of people it's not hard to read their body language, and in any event if you've taken a guest with you to the theatre, it's unlikely that you're going to refrain from discussing the show with each other on the way home. Besides, I doubt that the Daily Mail's Quentin Letts is suddenly going to decide that he adores an experimental feminist troupe from Bulgaria just because I've murmured my appreciation for them as we both make a grab for the cheese and onion crisps.

This no-conferring idea suggests that writing a review is somehow on a par with doing a GCSE in ICT and that it is a critic's job come up with the right answer and pass the exam. But when you write a review there is no right or wrong about it, simply a response to what you've seen, and if that response is informed by other's responses is that necessarily such a terrible thing? Might not hearing or reading other perspectives on a show actually enrich your views and deepen the conversation that you try to start around the show?

I ask because in Edinburgh, from whence I have recently returned, the critical rules go out the window. Apart from the Traverse press performances and some International Festival shows, there are no official press nights, so critics are seeing different shows or the same shows but in entirely different orders. Unless you spend the entire month living like a hermit, refusing to talk to anyone and averting your gaze from all the arts pages, then it's inevitable that you already know what a colleague thinks of a particular show before you've had a chance to see it.

Does this sully critical judgement? I don't think so. One of the most intriguing things about the most interesting writing from the liveliest bloggers is that it is often a response not just to the performance itself but often also to other writing which has already taken place around the production.

Work that is knotty, layered and more difficult than the average West End offering, often needs a period of processing that the traditional review – which requires the show is seen and reviewed almost instantly – simply doesn't permit.

When Three Kingdoms opened at the Lyric Hammersmith last year, some including myself, pointed to the reviews as an example of traditional critics just not getting a show which was operating outside of the narrow arena of much of British theatre.

But maybe it's just that instant responses are often shallower responses, and writing long-form reviews at more of distance, which reference and bounce off previously published opinion may lead to more considered and multi-faceted criticism.

It's not that one way is right and the other wrong, they are just different and, of course, the instant response is one of the things that makes theatre newsworthy which can only be good for theatre. It would be a great pity to lose it.

But being first isn't everything, and what theatre also needs is the widest possible range of the richest conversations, couched in the most varied forms, going on around it and with it. As the Edinburgh experience proves, the idea that critics should see and review shows in some kind of bubble of unsullied purity is absurd and increasingly outdated in an age where we are all connected and can share ideas and knowledge with such ease.