It happened again: someone I like and respect wants to know why I stopped following them on Twitter. Awwwwkward!

For all its utility, Twitter has one glaring flaw: it’s not a social network, it only plays one on TV, and this leads to problems when the twin roles of Twitter are confused.

First, there’s Twitter as information source. Second, and just as important, there’s Twitter as clubby, smoke-filled back room for casual chatter, meme dissemination and enforcement of group norms.

Facebook gets this, and resolves the issue of who you want to hear from vs. whom you want to be associated with via the ingenious Hide button, which allows you to secretly mute your friends without their ever being the wiser. If this existed in real life, everyone would be insufferably narcissistic and no one would even know it – and so it is on Facebook!

For those who use Twitter the most (and I am totally, utterly dependent on it as a source of insight and new story ideas) it’s a harshly Darwinistic world in which the Unfollow button becomes more necessary the more I use the service.

This is unfortunate.

My social network on Twitter should be expanding, but it’s not – at least not in terms of whom I’m following. Without an ability to hide, even temporarily, people whose tweets are less than maximally relevant to my current journalism gig, this is how it has to be: I simply don’t have the bandwidth to follow more people on Twitter.

And the more interesting and informative everyone becomes, the worse the situation gets – the utility of Twitter, it turns out, is self-limiting.

This all comes to a head when it comes time for one of my friends to send me a direct message on Twitter and – heyo! – they discover they’re persona non grata.

This is just bizarre. Twitter is ephemeral; it’s code. Unlike the real world, which has three physical dimensions is governed by the Pauli exclusion principle, there’s no reason this feature couldn’t be added to the arsenal of tweaks and gewgaws that have proliferated on Twitter since its most recent redesign.

So, how did the friend I’d unfollowed get in touch with me, in an era in which we are likely to know the daily travails of people whose conventional contact information (email, phone number, addresss) we probably don’t even possess? Why, he messaged me on Facebook, of course.

Twitter needs filtering tools. It’s time, in other words, that Twitter grew up.

Follow Mims on Twitter or contact him via email.