In my opinion, no single design is apt to be optimal for everyone. (Don Norman)

And that’s why we have personas. Now, without them, there are several defaults. Don touches on one of these – trying to be all things to all people. Other possibilities are designing for yourself or designing something so bland and noncommittal that you’re really not designing for anyone at all.

So, how to avoid all that? Right off the bat, you know that you can’t create a persona for every possible user or customer out there. You do have to narrow them down. 

But how many do you need? Personally, I generally let the data speak for itself. Now, I can guarantee that there will definitely be more than one. Chances are, though, that there won’t be more than 5 or 6. And, even then, you can typically divide your personas into primary ones and secondary ones. (Just make sure you focus on those primaries!)

The important thing is that you are designing for someone specific. But, if the personas have been designed properly – with believable stories, and real names, and realistic photos – it will be hard for the team to not do so. It's just the way the human mind works.

Once you have your personas, you now have several ways to do deal with them. You might, for example, come up with multiple designs. Or, you might want to design for one of your primary users, but make sure that other personas can still get to what they need (just don’t throw it in the primary users' faces). You might have levels – like in video games. Finally, you might want to simply make a business decision and focus on your primary personas (probably your main source of revenue anyway) and let the secondary ones go.

That said, I have also seen designs that do cover multiple audiences quite well. I’m thinking, in particular, of long sales pages, where the user simply keeps scrolling until they're sold. For the detailed-oriented type, they’ll be scrolling through the whole thing. For the shoot-from-the-hip type, it’s a few bullet points and a CTA. For the socially-oriented, reviews and testimonials are often what they’re looking for. For the hard-sell, show-me-the-money types, it’s usually showing your low fees, or your high interest rate, or how your price compares to other vendors.

Do note, though, that this is definitely the exception. The rule is exactly what Don says.

A bad website is like a grumpy salesperson. (Jakob Nielsen)

One favorite metaphor I like to use with design teams is that of simple, face-to-face, human interaction. Since I’ve worked in banking most of my career, that typically involves talking about bank branches. You know, where you wait in line for a teller, then go up to the counter, hand material back and forth, talk about the weather, then get a receipt and a lollypop and leave? 

What I like to do in particular is contrast the interaction that the user is having online with what the user might experience in a branch. Would a teller really be that abrupt? Wouldn’t they normally be a little bit more friendly in this particular situation? Would a teller really just stand there looking at you after you did x? Wouldn’t they say something to acknowledge you? Wouldn’t a teller give you a little more information than just that? Wouldn’t they explain some of this a little better? Wouldn’t the two of you have a fairly strong, agreed-upon recognition of what constitutes the beginning and the end of the transaction? Why did you leave the user just kind of standing there?

Now, I’m not saying go all out on anthropomorphization. I’m just pointing out that users already have a mental model in their head (and do tend to anthropomorphize computers anyway), and that keeping that model in mind can definitely help things run a little more smoothly.

Needless to say, these kind of IRL metaphors apply to any kind of online interaction – shopping, asking questions, searching for information, scheduling things … So, if you’re in the business of UX – IA, ID, graphic designer, content – this is going to apply to you too.

One thing I’ve found particularly useful in these situations is something I learned in linguistics, Grice’s maxims. These are basically the linguistic rules for meaningful conversation to happen:

• Quantity – where one tries to be as informative as one possibly can, and gives as much information as is needed, and no more.
• Quality – where one tries to be truthful, and does not give information that is false or that is not supported by evidence.
• Relation – where one tries to be relevant, and says things that are pertinent to the discussion.
• Manner – when one tries to be as clear, as brief, and as orderly as one can in what one says, and where one avoids obscurity and ambiguity.

Follow these in your designs, and you’ll have that human-interaction template down pat!

One final thing … I've only ever seen this quote all by itself. I'm wondering if it was originally combined with another of his famous maxims:

"The web is the ultimate customer-empowering environment. He or she who clicks the mouse gets to decide everything. It is so easy to go elsewhere; all the competitors in the world are but a mouse click away."

In other words, it’s lot easier to go to another site than go to another brick-and-mortar store. The Internet is not your local mall.