2010年在台灣有超過400萬人參與直銷，直銷產業的營業額在世界排名第10名，本篇文章有2個主要研究目的：（1）針對直銷業務員與顧客互動之職責外服務行為進行探索性研究，將不同類型的業務員職責外顧客服務進行分類；（2）據相關文獻探討，提出命題解釋業務員職責外顧客服務如何影響關係品質。研究結果顯示，業務員職責外顧客服務是一個多重構面的變數，包含情感支持、資訊分享、自願性社會互動以及實務上協助等4種不同的概念，本研究推論出4個重要的命題來說明業務員職責外顧客服務與關係品質之間的關係。直銷產業比一般行業更貼近「關係」之概念，藉由人與人之間的關係建立與人際間滿意與信任的累積，促使直銷事業運作，而達到複製及倍增的方式使事業擴展，而職責外業務服務正是直銷業務人員可運用之行動與做法。

There are more than 4 million persons are involved in direct selling in Taiwan, and retail sales by direct selling industries ranked tenth in the world. This article has two main research purposed: (1) an exploratory study designed to categorize different kinds of SERCS that are performed by salespersons interacting with their customers; and (2) to explain how SERCS might react to relationship quality. Results show that SERCS is a multidimensional construct, including emotional support, information sharing, voluntary social interaction, and practical assistance 4 different concepts. And this study infers 4 important propositions to explain the corrections between SERCS and relationship quality. In sum, direct salespeople should use more SERCS behaviors to gain better relationship quality and performance at the same time.