If people don't look at the URL there's no usability issue either way, so you might as well use the www version for technical reasons. This (sub-)discussion pertains to people who do look at the url. (And personally I agree that the www helps to denote a url, and so it's a net positive for users, or at least not a net negative.)

I saw a poster on a bus with domain.sydney sitting on its own line with no other context. I'd expect the majority of people had no idea it was a web address.

Yea, there should be an http:// before it on print media. Otherwise no one is going to type it into their phone. I've done that for a couple of projects that use non-standard domains

This would really depend on the demographic. Someone that is more technologically inclined would understand. However, appealing to the broad spectrum the general public would not. However, that example has to do more with the domain extension rather than www. Another example would be the .co domain extension example. In the western part of the country it could be easily recognize, but in the Midwest the demographic is much different and the general public may feel that a .co domain is merely a spelling error. It's all about your user demographic and their perception. Go with non www and then a redirect. Unless your demographic runs on 2G, either way isn't going to drastically affect your users. I would be more concerned about your file and images sizes than 100ms of a redirect.

There are a lot of offline ads (billboards, magazines, TV spots) that give out a URL.

Even as a technical person, I hardly use URLs apart from sites I know well.

I've noticed more and more recently a trend of billboards and things that just say 'Search [name]' instead of putting their URL there.

I've seen it too. That's a lot of confidence in their SEO.

I bet the sign itself serves as search engine optimization. If everybody starts searching for "foo" and clicks on my site in the result set then a reasonable search engine might bump my site up higher for searches for "foo."

That's an interesting hypothesis. It makes sense for the company both as optimization of their web pages for search engines and as making good impression on customers.

Not really, if I were doing this, I'd buy ads for the search term so I can guarantee (within reason) I'm at the top.

More likely a QR code these days

Thanks for sharing. I was a bit dense for a few minutes.

Haha, yeah I get it. But I scan QR codes all the time, maybe I'll take a photo and submit it.

People still use QR codes?

For loading two-factor authentication secrets. Or anything else you can think of that has too much information to convey with a short link. If you are directing people to a web site using QR codes then you're doing it wrong. Well, wrong now that everyone has realized just how limited QR codes are.

I do for any printed media. It makes it easier for people to look up the corresponding electronic version of a document. QR code has its uses, but tends fail when misused. QR code is best when interacting with it is strictly optional.

They ever did?

Well I think people did, once, but then immediately discovered it wasn't worth the effort.

They're great for managing parts in a manufacturer's storeroom. A QR code is more information-dense than a barcode.

I use them at bus stops to pull up live tracking

Right. By the time most people remember how to scan a QR code, they could've typed in the URL.

Is there a good (or even native) app to scan these on iPhone?

Everything I have tried is lackluster. I'm to the point where if something is qr only I just don't care enough and move on

RedLaser works well. Really well, actually. I'm not a QR fan, but hey every now and again I do scan one (usually out of some weird curiosity) and RedLaser is the best app for the job.

Opera mini does its job, and approaches QR codes the right way, being an input alternative to the keyboard reachable from the omnibox

Scanbot. Great app for scanning documents, but when you scan a QR code, it handles it.