Someone consistently criticising your organisation and its positions on  your facebook page or blog can be frustrating and disruptive. But the advice from the list was overwhelmingly that removing or barring commenters, however annoying, was a bad idea, and probably won't solve the problem anyway.

"What I’ve seen is that if you get rid of this troll, another will pop up… my favourite was the guy who had two identities and used to argue against his own posts in a forum I ran… it was hilarious!"

"But what’s the real problem here? Someone disagreeing with you in a community isn’t a problem. My view is that so long as its not doing any great harm, an opinion is an opinion. On the internet people tend to self-select and take part in groups they already agree with, so when someone doesn’t it upsets the equilibrium… he will either learn from the others and modify his views (highly unlikely), others will learn from him and strengthen their views (possible), get taken to task by other members and/or eventually get bored and go away."

"My position is no matter how much they annoy me to try and understand their position and exercise restraint. Censoring a negative poster also tells positive posters that there but for the grace of the all powerful moderator go they."

"If they aren't being sweary, racist or personally abusive to other posters, it's usually a good idea to let them be. It's horrible when some keyboard warrior decides to stamp all over your Facebook, but it's what 'social' means. Your site is a forum for users, not a place to solely promote your point of view."

Your users will probably represent you

"What you'll find is that your regulars step in and start telling them off, and it actually increases their loyalty to the page. And the troll isn't actually doing any harm."

"The way we have dealt with it is to just ignore him and let other supporters argue our point. Occasionally we engage to  ensure factually correct info is given, but generally we let him get on with his own mission of negativity."

"Could you nudge a couple of friendly supporters to post something to challenge the troll?"

It's important to have clear rules of behaviour so you can justify it if you do decide to intervene.

"In terms of a practical response, I would devise a social media commenting policy and publish it on Facebook, saying that people are encouraged to comment but warned that they will be blocked if they are off topic, offensive or rude to other commenters. Then if he goes too far you can block him and point to your policy – and ranters like that generally do start attacking others eventually or derailing non-related threads, etc.  Or get bored and wander off to annoy people on the Guardian Comment is Free site..."

You could try and engage them...

"My rule of thumb now is that it is worth trying engaging with (most) trolls once - that's based on my experience of the number of times that ends up in either a sensible exchange or a change in behaviour. Not guaranteed by any means of course, but happens often enough to be worth a try except in cases of particularly nasty trolling. However, when drawing up your rules (and also when considering what to do if the first engagement doesn't work out) bear in mind the risk that a troll's comments can put other people off contributing - just as one loud-mouthed person in a public meeting can put other people off contributing. The pattern and the impact on others will often matter; not just the narrow perspective on the particular words used on any one occasion."

"Just reply by stating your case clearly and calmly. If you don't agree with what a troll is saying, say you do not, and give reasons why you say this. Then leave them to it."

... and make sure you're setting a positive tone...

"One strategy we use is "Nicing people to death." Meaning, particularly early on, if you sense that someone may have an intent to rock the boat in order to get attention or whatever, an early friendly personal welcome can be very effective. It helps down the road if you have to clamp down on their guideline/rule violating behaviour."

...but don't feed the troll.

“Don't engage. Soon as you do, you're doomed to descend into a downward spiral of weird anti-logic.”

"If they've said something that absolutely can't sit on your site with no response, and you don't want to feed the troll, one approach is to say, 'But how does that point of view tally with the statistics on page 42 of this report? [link to vast, unreadable PDF by leading expert in whatever you're talking about]. It establishes your org as the experts in their field, and it obliges the troll to actually put some research into their next response. And very few trolls will bother with research. They're writers, not readers."

Maybe just be glad they're livening up your facebook page!

"You might want to learn to love the grit in the shell that is your troll. It's exactly this sort of 'nothing is wrong - bang 'em up' attitude that might remind your supporters why they wanted to defend your cause in the first place."

"Whilst we all love positivity and the reassurance we are doing the right thing, intellectual debate is important for organisations campaigning for change; we want people to provoke and challenge and even the trolls have a place in that as annoying as they are :-)"

And be reassured, it won't loom as large to your community
"You might feel that your entire page is dominated by a single troll, but what your supporters see is an occasional moment of trolling mixed in with lots of their friends' updates. As a result, Facebook trolling is less oppressive than forum and blog trolling, and can be more loosely moderated."

This article summarises a discussion on the eCampaigning Forum email list. Thanks to everyone who contributed.