Domino’s Pizza UK is attributing its 13% sales increase in the first half of 2010 in no small part to its social media prowess, specifically its integration with Foursquare’s location-based promotion system. But, as we know, correlation doesn’t necessarily equal causation. But the boast does have the web world buzzing: can a big social media push boost online sales so quickly?

The short answer is: it’s too soon to tell. Why’s that? There were a few other factors this year that could have pushed Domino’s UK profits up by 29%, notably, the World Cup and Britain’s Got Talent.

But no doubt Domino’s dive into social media experimentation is making strides. It has increased its fan base on Facebook and Twitter 30% to about 550,000 followers in the past three months; it started a Foursquare campaign in May to promote customers to check-in at its stores; and meanwhile, it has grown its e-commerce unit 61% in the past 6 months.

But critics aren’t entirely convinced. Reputation Online asks, “We’re always calling for case studies with measurable results and real figures included to prove the value of social media. But is this really the best way to do it?” And the Guardian posits that Domino’s  geeky spin on the numbers may have more to do with keeping Wall Street happy by investing in something new. It writes:

In other words, it appears [Domino's] does not want investors to assume there is a slowdown coming now these events are over.

A double-digit sales and profits increase in this brutal economy is an impressive accomplishment. Whether or not it can be directly attributed to, among other things, a new location-based social media e-commerce site, is probably not possible. But in citing the role of social media in boosting sales it opens up an important discussion topic that we can all now follow going forward: whether social media can in fact boosting pizza sales.