The Rights and Wrongs of Tag Clouds

I’m not obsessed with tag clouds, really I’m not, but I think they are the single most useful, yet criminally misunderstood and mis-applied UI device out there. I’ve written about tag clouds before, but this time I’m turning up the heat.

Controversy time: writing about “best practice” for tag clouds in terms of what fonts to use and other minutiae is the hallmark of the usability nerd. The other hallmark is forgetting – in this case utterly – to consider context. Whether or not a tag cloud is useful at all is 100% down to the context it’s in. Everything else is as near as dammit to irrelevant. The fact that few things in information architecture are as clear cut as this is particularly damning here. The one thing you have to understand in user experience design is context.

Tag clouds have a very particular use. They can instantly summarise to the user the informational “mood” of the site – the Zeitgeist; the drift, the “scene” – in a way that no other informational device can. They are in their element when there is a large amount of diverse information that you need quickly to get a handle on in order to decide whether you should spend more time on the site or not, or whether the information set is likely to be relevant to you. Once you have decided in the affirmative to this all-important issue, you can then use them as a primitive means of going to that part of the information that you are interested in (ie by clicking on one of the tags). They are not about navigation.

If you’re a designer, it’s immensely important to realise that it’s also very easy to have a tag cloud that is as useful to your audience as a bowl of sick.

Here’s an example of a good tag cloud journey (hate that word, but sometimes I have to use it). You go to a site which you’ve been told is a “designers’ community.” First problem: the context of the word “design” more or less determines what that word means, and whether you’re likely to join the community depends rather a lot on that meaning. It might mean visual design, business process design, systems design, structural design, or several other flavours of the term. Luckily, however, members of this site can attach tags to their profiles, and those tags are represented as a tag cloud.

Let’s pause there and consider what the user of the site should know once they have registered the existence of the tag cloud:

  1. The site is about “design” (whatever that means)
  2. The tags in the cloud are submitted by users registered on the site (it says so at the top of the cloud)
  3. The bigger the word in the cloud, the more common the tag

Instantly, you see the word “graphics,” “design,” “art,” “illustration,” “magazines” and “painting” are bigger than all the others. You then see that “digital” is very small and things like “rotoscoping,” “patterns” and “interaction” are completely absent.

Bingo. You now know what the site is about: it’s full of visual designers who have only marginal interest in digital media and probably all hate Jakob Nielsen, assuming they even know who he is.

Once again: there is no better way to known that for sure. The tag cloud is the only mechanism that delivers the right bang for the buck: near instant understanding of the data set. Sure, the graphic design of the site may offer some clues, or there may be some more scent around things like information about art galleries or whatever, but without the tag cloud you’d always be thinking “what do they mean by ‘design’?

Here’s an example of a bowl of sick. You go to a site that sells electronic goods like TVs, video cameras and hard drives. You are looking to buy a new monitor for your PC. On the home page is a tag cloud with the words “TV,” “monitor,” “camera” and “printer” all in the ascendant. It also has lots of other names of gadgets and consumables in the cloud.

The tag cloud takes up a lot of space, but there’s no way to know how the cloud is constructed. Is it numbers in stock? Is it different models? No explanation. Not even an apologetic “What is this?” link.

So how the hell is that in any way useful to you in the context of shopping for consumer electronics? Sites selling electronic goods are not very mysterious places. They might not stock some esoteric widget that you are looking for, but you can find that out by using the search. The one thing you are not there to do is marvel at the fact they have more cameras than printers. The fact that you can’t tell what the cloud is showing you also goes down like a lead balloon. Tag clouds should be about instant understanding. Using them as horizontal navigation is just idiotic.

So, best practice in tag clouds is nothing to do with line spacing or sorting options – it’s about considering the context and making sure people can easily understand how they are constructed.

The good example.

The bowl of sick.