Increasingly, when journalists now write headlines for the web or for social media, they specify the medium or format involved. They shout VIDEO and AUDIO in caps at the start of the tweet or post; MAPPED or INFOGRAPHIC; INTERVIEW or LIVEBLOG.

Sometimes the medium or format is implied more subtly, with a call to action: we urge users to ‘Watch’, ‘See’ and ‘Listen’. But we also invite them to ‘Join’, ‘Meet’ and ‘Find out’.

Users choose the medium as well as the message

Why do we do this? Part of it is that we recognise that the medium is something special; that users often make a choice based on the medium itself.

But I think putting the medium/format front and centre is about more than just user preference: it’s about abundance and scarcity.

In a market of information abundance, of copy-and-paste reporting and opinion-as-journalism any content with an original element is unusual.

Imagine the average Facebook user: that person’s feed contains over 1,500 items on any given day. Not only does Facebook need to make choices about which items to show (and the medium makes a difference), but the user has to too.

Then there are the other social networks they’re on; the search results they see; email newsletters, RSS feeds, text alerts.

So how do they choose what to click on?

The scarcity principle and the new ‘exclusive’

This is the scarcity principle: on the web, original information is scarce; audio or visual content is scarce; live-ness is scarce. Above all, attention is scarce.

The reason why we brand our content with ‘VIDEO’ or ‘LIVEBLOG’ or ‘INTERVIEW’ or ‘LISTEN’ is the same reason we used to brand it with ‘EXCLUSIVE’ or ‘PHOTOS’.

It’s just that the our competition has changed – and with it, our unique selling points.

The competition is no longer a dozen other front pages: it’s a thousand updates.

Against that competition, then, we are having to make a case not even in the first 140 characters, but in the first 14 characters: why should I click?

So what I think those terms really say is this:

• INTERVIEW: I actually spoke to someone else
• LIVEBLOG: I’m actually where things are happening (probably)
• AUDIO/VIDEO: You will see/hear the raw material rather than my interpretation (hopefully)
• INFOGRAPHIC: I took some care to bring a bunch of important numbers together (or I’m selling something)
• MAPPED: I took some care to sum something up on a map
• GALLERY: I took some care to collect the most important images together
• MEET: I actually spoke to someone else
• WATCH/LISTEN: You’ll experience something (honest)
• SEE/LEARN HOW: You’ll learn something
• JOIN: You’ll be part of something

There are probably many other examples I haven’t thought of – but that’s a good list to start with.

And just to illustrate those – here are some more examples in practice:

Infographic: The GOP needs a “net” gain of 6 seats to take control of the U.S. Senate. A look at the possibilities: http://t.co/ffxcpm56Oi — USA TODAY (@USATODAY) November 4, 2014

Mapped: Which health economies would be candidates for the mooted “whole system” special measures regime? pic.twitter.com/WLwxOgbpVW

— HealthServiceJournal (@HSJnews) October 29, 2014