As we’ve posted before, social commerce goes beyond straight social media sales, and takes into account both customer service and social reach. Online retailers who focus on social commerce are expanding their reach—and improving visibility, conversions, and sales.

Over at the Fast Company blog, Altimeter Group’s Brian Solis posted a rundown of why social commerce is so important.

His take: Social psychology plays a big part in the consumer purchasing process—and it’s a driving force behind the increasing popularity of social commerce strategies.

Social psychology tells us that prospects will turn to friends for advice when they aren’t sure what to buy. Solis points to an infographic from TabJuice that lists some hard numbers, including this stat: 81% of consumers receive advice about a product from friends and family via social networking sites.

That means social commerce isn’t about just getting a prospect to “like” your page on Facebook or follow you on Twitter. It’s about getting them to talk about your products and recommend your company to friends, family, and followers.

And more retailers are creating features and apps that make social media an integral component of the buying process in order to tap into that influence.

Four retailers and their social commerce strategies:

1. JanSport

JanSport’s spin on social makes it easier than ever for prospects and shoppers to tell everyone how they feel about the company’s products. From each JanSport page, visitors can post directly to Facebook, share the product they’re viewing, or chat with friends without ever leaving the company’s website. Research says prospects still want to complete purchases through a retailer’s main website, but adding Facebook features to your website allows prospects to continue their social media conversations while they’re shopping. The result: JanSport’s social efforts have paid off with a 49% increase in order value, a 39% increase in conversions, and a 147% increase in time visitors spend on the site.

2. Karmaloop

Karmaloop’s Rep Team adds online networking to street team-style promotion. Rep Team members are given a unique “rep code,” which they share with friends, family, and more. That rep code gets users 20% off of their next purchase at Karmaloop—and racks up incentive points for the Rep Team member every time it’s used. The result: Online word of mouth pays off for reps and new prospects, plus Karmaloop is building a dedicated network of online fans.

3. Target

Target’s Give with Friends app lets fans create a Target eGiftCard through their Facebook accounts. Fans simply select the recipient, then invite their friends to add to the gift card, too. Once all the contributions are in, Target delivers the eGiftCard directly to the recipient. The result: A group of friends or co-workers can pitch in to buy a gift without ever leaving Facebook—and the app helps Target generate even more fans when users ask their friends to pitch in.

4. Shop My Label

Shop My Label’s website allows users to curate their own online stores and fill them with the clothes, jewelry, and accessories they love—and have them promoted by Shop My Label through Twitter and Facebook. The result: Shoppers not only become style experts, but  it’s easier than ever for them to tell everyone they know about the products they love. Plus, Shop My Label puts users in their social media spotlight—a favor we bet their fans will repay.

In all four of these cases, retailers are improving their reach and visibility—and sales, in some cases—by developing websites, promotions, and apps that make social commerce an integral part of the purchasing process.

How can your company incorporate social commerce into its online presence? It’s crucial for online retailers to ask that question, develop a social commerce strategy, and act on it now.