National Australia Bank said its new social media "break up" campaign has led to an increase of one point in mortgage share in just a couple of months with minimal cost.

National Australia Bank, which has found itself repeatedly explaining and covering for batch processing-driven glitches in its payments and other IT systems over the past year, had some good tech news to report last week. Its microsite attacked its rivals, saying the bank was "breaking up" with them over presumably higher interest rates.

The bank used Twitter, Facebook and YouTube to spread its adversarial message, gaining both buzz and followers. Chris Smith, National Australia Bank's general manager of personal banking, said at a CeBIT tech show in Sydney last week that the bank gained more Twitter followers and Facebook fans as a result of the campaign.

NAB reported a corresponding 50% increase in credit card applications, 20% increase in mortgage applications, 35% increase in queries from other banks' customers and an increase of 1% of mortgage market share — all stemming from a campaign with minimal to no cost for the bank.

Smith said the quick success shows that banks that ignore social media are doing so at their peril.

The bank, which has about 200 IT and marketing professionals working on social media marketing, is moving on to phase two of the "break up" campaign, called "We're Not Popular with the Other Banks," a slogan that will appear on Facebook, Twitter and YouTube — again positioning NAB as a destination for low-cost home loans.