With the four big social networks (YouTube rounds out the pack) now firmly established, many marketers are focused on getting more from the social capital they already have. Cisco Systems and Oracle Corp. are the latest tech giants to put thousands of employees through formal social media education programs, and IBM Corp. has trained 1,000 channel partners in a social media “boot camp.” Even nontech firms such as Aon have fielded recent campaigns that relied heavily upon employees to spread the word. The results: Cisco reported that in one campaign last year, employee-driven tweets accounted for 41% of social reach. Companies are also investigating new uses of social tools in support and recruiting. More than 70% of companies polled in a 2012 Social Media Today survey that drew more than 500 respondents now use social media for customer service, with customer satisfaction and loyalty cited as the main drivers. Satisfied customers spend more, and keyword monitoring can reveal product problems before they become a recall headache. Social media has also become ubiquitous in recruitment, with more than 90% of U.S. companies regularly seeking talent through social networks, according to a Jobvite survey of more than 1,000 human resources and recruitment professionals in June. LinkedIn, which started as a matchmaking site for job-seekers, has evolved into the top social network for b-to-b marketers. It crossed the 200 million-member mark in 2012. While Facebook struggles with its business model, LinkedIn stock has almost doubled in the past year. The network's diversified business has drawn raves from investors, and surveys consistently place it ahead of all others in b-to-b effectiveness. Last year, it snapped up the underappreciated Slide-Share and overhauled its company pages to make them richer lead-generation vehicles. “LinkedIn is on a path to replace email as the primary means of business communications in the next several years,” said Jim Cahill, head of social media at Emerson Process Management, which helps industrial companies automate production, processing and distribution. “I see more engagement there than I do in Twitter and Facebook.” Google+ is the dark horse worth watching. More than half a billion Google accounts are Google+-enabled, although actual use is much lower. Google is courting businesses to set up shop on the network, dangling improved search performance as an enticement. It's also positioned Google+ as an integration point for all it's applications and services. “Google+ is to Facebook and Twitter what Macintosh is to Windows: Better, but fewer people use it and the pundits prophecy that it will fail,” wrote Guy Kawasaki in his book “What the Plus!” (McGraw-Hill Cos., August 2012). If he's right, then Google could do worse than follow Apple's lead.