Think about it, who is your favourite advisor when it comes to finding your next, undiscovered restaurant? Your mum or perhaps your best friend? Sometimes they might not give the best advice, luckily you have kind strangers who write reviews online, which you can consult. Review platforms such as Yelp.com, enable people to write and read reviews on products and/or services. But how do businesses handle marketing efforts in the context of electronic word-of-mouth (eWOM)? This is an important question for managers since the rise of the Internet has changed how they allocate marketing expenditure, turning more to online advertising (Lu et al. 2013), but is this effective? To answer this question Lu et al. research the influence of promotional marketing on third-party review platforms.

What was their approach?
Lu et al. examined the impact of online coupons, keyword sponsored search and eWOM on weekly restaurants’ sales using a three-year panel study. They focused on restaurants since going out to dinner is a high-involvement service and eWOM is particularly important for high-involvement products and/or services (Gu et al. 2012). With high-involvement products customers spend considerable time searching for information before purchasing. Lu et al. collected their data from one of the largest restaurant review websites in China. Online coupons are displayed on this platform and the keyword sponsored search works as follows: restaurants buy keywords and when users search for restaurants using that keyword, the restaurants will be displayed at the top of the platform’s search results.

Key insights
One of the key insights Lu et al. found is that both promotional marketing and eWOM have a significant impact on sales. Keyword sponsored search and eWOM have a positive impact on sales. Likewise, offering online coupons has a positive impact on sales, however this relationship is not present for coupon value, indicating that the presence of online coupons is more important than their value since it increases awareness among users (Leone and Srinivasan 1996). Another key insight is that interaction between eWOM and promotional marketing is significant. The interaction between eWOM and coupon offerings is negative, indicating that they substitute one another and thus only one is needed to attract sales. On the other hand, the interaction between eWOM and keyword sponsored search is positive, indicating that they complement one another and together increase sales. Furthermore, if you would use both promotional marketing tools simultaneously, this would negatively impact sales since too many marketing tools  at the same time is experienced as too intrusive by customers. Altogether, these insights highlight different sources of information, with different levels of credibility, while still both sharing the power to inform and attract customers.

Looking to promote your business?
The study’s strength is that it presents some very useful advices when it comes to using promotional marketing in the context of eWOM. First of all, it is good to know that allowing promotional marketing activities on third-party platforms does not hurt the platform’s credibility and thus indicates some interesting marketing possibilities. According to Lu et al., you should stimulate users to generate more positive eWOM since this increases sales. Businesses could use online coupons to get customers’ attention, but if the volume of eWOM is high, this tool becomes less effective. In the case of high eWOM volume, businesses should rather buy keywords to increase sales. However, businesses should not use these two promotional marketing tools simultaneously since this decreases sales, rather they should focus on the tool that is most suitable for them.

Although these insights are useful, managers should note the study’s weaknesses. One of these weaknesses is the study’s generalisability. Firstly, the study only included restaurants from Shanghai, while other academics indicate the presence of cross-cultural differences (King et al. 2014). Secondly, the study focused on high-involvement products, while many studies examine low-involvement products, e.g. books and films, and find that eWOM has a significant impact on sales (Chevalier and Mayzlin 2006; Duan et al. 2008). Thirdly, the study focused on one platform, while other studies indicate that eWOM across platforms can impact sales (Gu et al. 2012). Therefore, future research could focus on whether the study’s results also apply cross-culturally, across different product and across different platforms. Another weakness of this study is the limited dimensions of eWOM and promotional marketing captured. For instance, Chavelier and Maryzlin (2006) indicate that the length of reviews also influences customers’ purchasing behaviour. Besides, the measurement of promotional marketing is two-fold, while other options such as banners or pop-up ads also exist. Future research could therefore investigate whether results differ for other promotional marketing tools and if adding more dimensions for eWOM might indicate different results. To conclude, although the paper has some weaknesses, it does not overturn the practical implications, managers should however be cautious and decide whether the study applies to their specific situation or if their situation deviates from the study’s setting.

References
Chevalier, J.A. and D. Mayzlin (2006) ‘The Effect of Word of Mouth on Sales: Online Book Reviews’, Journal of Marketing Research 43(3): 345-354.

Duan, W., B. Gu and A.B. Whinston (2008) ‘The dynamics of online word-of-mouth and product sales – An empirical investigation of the movie industry’, Journal of Retailing 84(2): 233-242.

Gu, B., J. Park and P. Konana (2012) ‘Research Note – The Impact of External Word-of-Mouth Sources on Retailer Sales of High-Involvement Products’, Information Systems Research 23(1): 182-196.

King, R.A., P. Racherla and V.D. Bush (2014) ‘What We Know and Don’t Know About Online Word-of-Mouth: A Review and Synthesis of the Literature’, Journal of Interactive Marketing 28(3): 167-183.

Leone, R.P. and S.S. Srinivasan (1996) ‘Coupon face value: Its impact on coupon redemptions, brand sales, and brand profitability’, Journal of Retailing 72(3): 273-289.

Lu, X., S. Ba, L. Huang and Y. Feng (2013) ‘Promotional Marketing or Word-of-Mouth? Evidence from Online Restaurant Reviews’, Information Systems Research 24(3): 596-612.