Examples of strong building relationships through social media, in  a blog post by Yael Davidowitz-Neu, a Sales Strategy Analyst at Google responsible for analyzing consumer behavior, search trends and market dynamics: 

Building Long Term Relationships

While it’s true that the web has made building individual relationships cheaper and easier than it used to be, this doesn’t mean that businesses can necessarily expect to build deep connections with their entire customer base; in many cases, this is neither feasible nor cost effective. However, if a firm focuses on building brand loyalty with a small subset of customers, they may find that it has an exponential impact.

Let’s look at a few examples of companies that have done this successfully:

Yelp’s Elite Squad: Yelp operates a social networking, user review, and local search website for members to post reviews and get user feedback on local businesses and restaurants. The Elite Program is a way for the Yelp to reward its most passionate users for making their site “funny, useful and cool” by providing them with exclusive offers and members only events. This allows Yelp to strengthen loyalty among Elite Squad members, offers an impetus for wanna-be-members to post additional reviews; and, makes the site content stronger – keeping the broader community active and engaged.

The Leukemia & Lymphoma Society’s Team In Training (TNT) Program: The Leukemia & Lymphoma Society is a charitable organization focused on fighting blood cancers. To raise funding, they developed a variety of programs to expand their outreach, including The Team in Training Program, which offers group training to those interesting in running a marathon to raise money for the cause. TNT encourages trainees to leverage the power of their personal networks, by providing participants with a personal, customizable microsite for reaching their fundraising goals by getting donations from friends and family. The microsite functions much like a Facebook Page – marathon participants can share their goals, visitors are able offer supportive messaging on the participant’s wall, and donations can happen directly on site.

Lion Brand’s Lion Brand Notebook: Lion Brand is a yarn company that has been in business for over a century. To build their online presence and appeal to passionate knitters, Lion Brand developed a bi-weekly podcast and corporate blog, They also helped to facilitate offline “knit-alongs” (shared knitting projects), by helping interested parties to find others in their local area looking to get involved. Lion Brand Yarn found that their customer outreach strategy drove impressive e-commerce results – those who visited the company’s blog were 41% more likely to buy at the Web site.

The rest of the article is also very good, in terms of strategic suggestions for building relationships through social media.