资料：For promotions to remain effective, RT company has to analyze the impact of different campaigns. Word of mouth promotions can be more difficult to measure than some traditional methods of promotion. Although healthy sales are an important measure, RT uses other measures to evaluate the effectiveness of its activities. For example: Setting targets for sales returns from the smaller promotional activities. Evaluating the amount of editorial coverage its activities receive in the media. Measuring the number of blogs related to RT"s products and the frequency of comment on these blogs. Evaluating the online influence of RT activities in the social media. For example, on Twitter there are around 260000 followers of RT activities.On Facebook,more than 21000000 consumers like RT. Conducting an annual brand health-check with consumers to ensure that they like the brand. Measuring the outcomes of RT promotions is not just about return on investment. These figures do not create the whole picture. This is because it can be difficult to value word of mouth promotions on paper. Sales returns do not take not account other factors such as longer-term brand loyalty. What is the passage about?