There are these two young fish swimming along, and they happen to meet an older fish swimming the other way, who nods at them and says, “Morning, boys, how’s the water?” And the two young fish swim on for a bit, and then eventually one of them looks over at the other and goes, “What the hell is water?”

(David Foster Wallace)

It’s not every keynote at Congress that begins with a quote from an obscure speech from a cult postmodernist thinker, but this is how Twitter CEO Dick Costolo began his address in Barcelona last week. He went on to reference everyone from the Rwandan president Paul Kagame to Christiano Ronaldo to Chinese artist Ai Weiwei – all prominent Twitter users. He said little about smartphone platforms. Or LTE. Or how operators should tackle rising levels of mobile data usage. He may have immediately followed Microsoft’s Steve Ballmer on stage, but Costolo often sounded like he was beamed in from another planet such was his apparent disinterest in the hot topics of the day (if he had a view on the Nokia/Microsoft tie-up, he kept it to himself).

Twitter’s view on the mobile industry isn’t one of ambivalence, of course; it merely approaches the industry from an entirely different standpoint. And this is what made Costolo’s keynote so compelling. In an industry still dogged by fragmentation and interoperability issues, Costolo positioned Twitter as a ubiquitous tool that already works on every possible device – from the most high-end smartphone to an ultra-low cost handset capable only of SMS. Indeed, the only reference he made to any operator at all was Digicel Haiti, a firm Twitter worked with to provide an SMS service during last year’s earthquake and its aftermath. Despite being a partnership borne out of disaster, Digicel had become “one of the most effective operators in marketing Twitter to users,” according to Costolo.

Costolo’s overriding vision for Twitter with regards to mobile appears to be to establish it as the new SMS – a service so ubiquitous and simple-to-use that it becomes barely noticeable (the “water” in David Foster Wallace’s fish analogy). He noted that 40 percent of all tweets now originate via mobile, but that work still needs to be done to more tightly integrate the service into devices at a fundamental level.

But Twitter goes beyond messaging and Costolo put forward a convincing argument that the service should now also be considered a content platform in its own right. Many new users apparently do not tweet at all but simply follow content related to their interests, turning Twitter into what Costolo called a “consumption experience.” And then there’s the shared interaction that Twitter can provide around events that bring people together: such as sports and “must see” TV. Some canny brands such as Audi, Costolo noted, are already tapping into the potential of these experiences from an advertiser’s point of view – and in doing so answering the tiresome question of how Twitter plans to generate revenue from its unique platform.

Hopefully, Costolo’s keynote made a deep impression on the mobile execs that watched it last week. Mobile phones may be ubiquitous, but – SMS aside – mobile services are not. Twitter provides a ready-made solution to this problem. The mobile industry should dip its toe into the water.

And then ignore the water.

No, I still don’t get it…