In Korea’s telecommunication market, the total adult population owns at least one or more mobile devices, with the number of new users decreasing every year. This market structure cannot prevent Korean telecommunication companies to play a zero-sum game and most of the campaigns that were intended to raise sales eventually turned out to be effective for just a very short period of time.

In order to carry out promotion activities that last for long periods and are fundamental, it needs to improve and build up a close relationship with customers. From that sense, SK telecom's 'The slowest letter' campaign was very powerful. We excluded any type of promotional messages that said "Please become a SK telecom customer." Instead, our messages were refined but strong enough to say "You will not be able to participate in this campaign unless you are a SK telecom customer."

2. Spent 6 months to develop this application and was launched through Google playstore, Apple app store, and the Korean T store on 16th September, 2014. We introduced this app through newspapers and TV commercials that tell stories of ordinary people to which customers could relate to easily. During the process, we found out several Korean celebrities, including figure-skating queen Yuna Kim, have started to use this app. Immediately, we uploaded and promoted their proof shots through our facebook page. Participation increased steadily and on the last day of the campaign, the server went down due to high access concentration.

- 481,868 downloads in 3 months

- 167,000 letters were actually sent (34% response rate)

- ‘Most preferred brand’ in telecom category increased by +4.5% (IPSOS, Oct 2014)

- ‘Most preferred brand’ in LTE service category increased by +5.6% (IPSOS, Oct. 2014)

- Increased user intention found online (“I want to use SK Telecom because of this app”)

- More than 3,600,000 views for TV ad on YouTube, unusually high for brand-generated content

- Received media attention through Korean celebrities’ participation, parodies on TV programs, etc.

- <2014 Consumer Satisfaction Management Awards> 1st place in telecom category

The campaign succeeded in achieving SK Telecom’s long-time goal- increasing brand preference. Online/mobile promotions usually garner less than 3% response average from consumers in Korea. However, this promotion attracted 34% response rate, even with the rather complicated process of registering and writing the message. SK Telecom also received an award for consumer satisfaction.