It is a touch ironic that a local mobile operator, SmarTone, should announce it is reining in the provision of unlimited data on the same day that Facebook unveiled plans for a stock market listing to finance the phenomenal expansion of the social networking business. After all, extraordinary market valuations for Facebook of up to US$100 billion rest partly on the rise of the smartphone, as well as the spread of internet connectivity. About half of Facebook's 850-million-odd users tap into the network on mobile devices and this is where most of its future growth is expected to come from.

In Hong Kong's cutthroat market, mobile data access has become a factor in market share. But SmarTone is to stop offering unlimited data plans to new subscribers starting a week from Monday, rather than comply with a directive by the Office of the Telecommunications Authority compelling operators to disclose hidden limitations that have crept into the plans. Such has been the explosion in the number of smartphone users that networks are struggling to meet demand, and some have resorted to slowing down data transmission speed for heavy users. SmarTone will now cap data use under its HK$298 monthly plan at two gigabytes, which will still enable people to browse 1,000 webpages, 10,000 e-mails or watch five hours of video. Its decision could be the cue for other companies to follow suit, thus marking the end of unlimited data access for the city's smartphone users.

Apart from genuine heavy users, who will have to pay as they go beyond the 2GB cap, this may not be a bad thing. Communications technology has made the world a better place for billions, but from the outset mobile phones could be intrusive enough - from weddings to funerals, let alone in everyday social discourse. A cap on data access may prompt people to wonder whether they are becoming addicted to the temptation to tap in, at the cost of interpersonal relationships and communication, and induce a positive behavioural change with lifestyle benefits. If that does not work, the pay-as-you-go principle might, if it results in an eye-watering mobile bill.