It doesn't matter...

"Looking at this as purely an external facing pseudo metric seems hugely unauthentic.  The only time it affects your credibility is when you follow no one (or a very, very few) that just shouts out ‘I’m not listening’! "

"The only people who really care about that ratio of followers to followed are people who treat Twitter as an  'I've got more followers than you' competition. They regard following lots of people as 'cheating' in the game they imagine we're all playing against them.

"If you are trying to make those people think of you as important and influential (and they do include quite a lot of bloggers and journos), then you need to trim your following list. Otherwise, follow back. It's polite."

“The only time the ratio and score mentality comes into play is when you start looking at tools like Klout, which are often now built into other tools, like Cotweet. I think ratio plays a part in your Klout score, but there are so many other factors such as whether you're being retweeted by people who are influential, how much engagement you get with your tweets, etc... It's probably worth being aware that you shouldn't follow everyone who follows you (unless you actually want the cheap US pharmaceuticals), but following a lot of people definitely isn't a problem."

"Of course, it looks good to be following the other biggies in our sector – organizations, charities, celebs, MPs etc. But the ratio thing – I would only worry about that if our followers really cared (and I’m not convinced they do)."

And has benefits

"Also worth keeping in mind that that the more people you follow, the more likely you are of being 'found' in their lists of followers. I'd say trying to keep the ration 1/1 all the time is the way to go."

"My personal policy is to follow anyone who follows us, and seems a valid user (whenever I get the time to) - that way, they can at least DM us if needs be. Of course, I'll enter into discussion with anyone who @s us."

"the 'I'm not listening' Twitter accounts are the ones I regularly cull from who I'm following. Tools like Formulists even create simple to manage lists of accounts that don't follow you back that you can then cull. [Ed note - formulists is no more, but the site lists out some alternative tools.] Twittiquette has moved on since 2006, but on the simplest level if someone / some organisation doesn't want to engage with me socially, then I'll drop 'em."

“I tend to view people/orgs that don't bother to follow back as, at best, displaying their ignorance of the ethos behind Twitter and, at worse, their arrogance. I remember sitting in a twitter training session a few years back where small NFPs were advised to adopt an organisational, broadcast approach - inject no personality, using it to broadcast messages only and not enter into discussion (I disagreed, quite vocally, along with a couple of others in the session).”

Supporters like to be followed back

"I think – ignore it! People have responded so well to us when they see we’re following them back – because they are real people behind the twitter avatar after all. It helps them see that we care about their support, they’re important to us and surely that will encourage them to RT, share info from us with their friends, and really feel a part of our social movement."

But it does affect what you can take in

"The practicality of the matter, though, is that you clearly can't read your twitterstream in any meaningful way once you're following more than a few hundred accounts."

"...lists have to be the only way of setting up a meaningful two-way relationship while still tuning out the noise”

And beyond a certain list size – a follow-back is meaningless

"I might be a bit of an exception here, because my colleagues and I manage a pretty big twitter account (we currently have over 390,000 followers), but I think at some point, people realise that a follow back is a bit meaningless. This is why we stopped automatically following back people.

"I don't think it's ignoring the ethos of twitter, quite the opposite. A lot of people will find it way more meaningful if our account answers one of their questions with a DM or an @ reply than if we start following them and then never see any of their updates in our stream. A 1:1 ratio for us wouldn't mean much."

"Not sure where that magical number of following too many people is (10,000? 100,000?) but I'm pretty sure our account is beyond it."

Engagement is the important thing, not Big Numbers

"Forget the numbers and ratios as an end in themselves, focus instead on engagement and attracting your target audience.  A year ago we had 16 followers and we're now up to 973, but the majority are exactly the target audience we wanted - the community, local media and bloggers, historians, people interested in architecture and windmills - so we're always directly talking to the people we want to talk to."

Recommended reading: Four reasons why nonprofits should follow more on Twitter'

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