Earlier this month, we published data examining quarterly social login and sharing trends across the 365,000 websites using Janrain Engage. The data demonstrated Facebook’s position as the most popular choice for social login. But our findings also emphasized the value of choice, given that 58% of online users prefer registering on sites with a social identity from Google, Yahoo!, Twitter or other networks.

Similar to prior analyses, we have taken a sampling of sites in prominent industry verticals to measure trends in consumer login preferences. While the overall story arc is similar across these verticals, there are disparate preferences within each segment that merit attention.

On media websites, Facebook leads in popularity with 43% of users preferring to register or login using their Facebook profile. Yahoo! and Google are running strong as the second and third most popular providers at roughly 19% apiece. Despite a modest decline over the past two quarters, Yahoo! continues to perform best in this vertical – perhaps as a result of its realignment as a content network during the past several years. Twitter’s share within this segment has yet to accelerate, but its potential for future growth makes it worth keeping an eye on, particularly given its focus as a network for content discovery.

For marketers and digital strategists managing these types of sites, effective engagement with readers begins by offering incentives for registration. Whether it is to comment on news articles, join a vibrant community, or unlock premium content, visitors need a compelling reason to share their personal information and create an account on your site. Bicycling Magazine, which is a property of Rodale, makes the benefits of registering clear to its visitors. And because registration is offered with a social identity, the process is a breeze, requiring only two clicks. Goodbye lengthy forms and struggling conversion rates.

Similarly, The Sun, one of the largest daily newspapers in the United Kingdom, prompts readers to easily register or login with a Facebook or Twitter identity in order to post comments on articles.

Social login implementations such as these generate tangible business results for content and community sites. For example, lifestyle magazine Divine Caroline, a Meredith property, saw a nearly immediate 12% increase in registrations after adding social login to its registration flow.

On entertainment and gaming sites, which tend to be more community-oriented, Facebook again leads the pack by a wide margin. But 57% of users prefer to login with a different social identity. Within this vertical, Google earns 23% share as the second most popular network. It’s also worth noting that while Windows Live (Hotmail/MSN) maintains an 8% share of social logins on entertainment and gaming websites, this is a 6% decrease from the previous quarter.

More than ever, people are using their social networks to share interesting news articles and content with their friends. On media sites, it is now common to be presented with the option to share an article comment with Facebook friends, Twitter followers or LinkedIn connections.

Across the websites of all Janrain Engage customers, Facebook and Twitter are far and away the most popular sharing destinations, but Yahoo!, LinkedIn and MySpace maintain preference on niche sites that are catered to their audience (B2B sites for LinkedIn and music sites for MySpace).

Creating a viral loop of referral traffic between your site and the social networks requires more than just dropping a few generic share buttons on various pages. Social sharing needs to be contextually integrated into the user experience on your site. For example, VH1, an MTV property, lets music fans share videos and their reactions to them after posting comments.

When implemented strategically, social sharing can become a steady and valuable source of qualified traffic to your site. Citysearch, for example, generates an average of 28 referral visits to its site each time a member shares his or her review of a local business to a social network stream.

Social login and sharing open the door to collecting a rich amount of profile data from a user’s social network account, and each social network provides a different set of profile data on their users. This information can be used to speed registration, create community by leveraging a user’s social graph (friends), and enable personalization of content or email campaigns based on a user’s demographics or interests. Here is a look at the profile data that users can choose to share with your site from their social network:

Social login has achieved significant adoption on media and entertainment websites during the past several years. Understanding how consumers leverage their social identities to connect and interact on these sites helps you tailor content your audience, improve engagement and drive higher CPMs from advertisers.