Checking Twitter over breakfast this morning, my feed was alive with furore over Google’s decision to retire Google Reader, and I’m not ashamed to say that I joined in, too. Of course, we all know that RSS isn’t particularly well-adopted outside the web / tech industry, so it’s perhaps not entirely surprising to see Google kill (what they consider to be) a niche product. What is worrying, though, is that this is yet another example of a product meeting its demise because it’s free.

How many apps and services that you know and love are only in existence because they have a business model? Or, put differently: how many of them would be killed if they were bought by Google? Apparently SnapSeed for Mac is another casualty in Google’s spring cleaning. (I can only hope they don’t kill the iOS version, which is — in my opinion — one of the best apps out there.) As Dalton Caldwell said in App.Net’s manifesto, ‘with a free, ad-supported service, [the service’s] customers are advertisers.’

Of course, there are exceptions. Google killed Sparrow last year, even though it was a paid app. It’s unlikely Gmail or any of Google’s core services will disappear purely because they’re free. And there are plenty of excellent free apps out there with no clear business model. But I still think that Google Reader’s demise highlights our over-reliance on free services; specifically, free invisible services. It struck me that this is the first time I’ve been upset about an invisible service being killed off.

I say ‘invisible’ because I’ve never, ever used Google Reader’s web-based front-end. I use it merely as a back-end service to sync feeds within Reeder, which I have on my iPhone, iPad, and Macs. Perhaps these invisible services are the most important in our digital lives, and therefore leave us the most vulnerable. Imagine if DropBox closed its doors. I think my world would implode.

Except that DropBox is a profitable company, with a service that is paid for by its users. Its customers are users, not advertisers.

I like Google a lot. I think they put out some great products, and I believe that they’re genuinely improving our lives with their forward-thinking technology. I want Google Now on my iPhone. I can’t wait to try Glass. If they build the first robots and flying cars and spaceships to Mars, I’m there. But I think we should all remain just a little bit sceptical about the advertising revenue at the core of the company and the free products — from any company — that are not funded by users’ money.

Meanwhile, in the aftermath, now is a great time to fall back in love with Shaun Inman’s Fever (although it’s worth reading Shaun’s advice). I was a long-time Fever user and only let it slide when I decided I needed cloud-based syncing across multiple machines, but I’ve now realised that Reeder can use Fever as a back-end. Sadly that’s only Reeder for iPhone for now, but I expect the iPad and Mac apps will see an update pretty soon in the wake of yesterday’s announcement. There are plenty of other alternatives out there, too. And, as Marco Arment suggests, perhaps Google Reader’s death will foster a new wave of innovation for RSS apps and service.

That’d be nice.