As recently as five years ago, businesses small and large and nonprofits still seemed puzzled by the value of social-media platforms, then derided as a what-I-had-for-lunch frivolity.

Even now, they struggle to quantify exactly what impact their investments in social media and Web content produce for their bottom lines.

But the strategy is as much defensive as offensive, as it grows increasingly clear that companies with no digital presence are becoming invisible to many consumers.

Businesses that don't embrace social media as a marketing tool do so at their own peril, warned Steve Nicholls, author of Social Media in Business.

"Any company ignoring it is already behind," he said.

The laggards miss out on an increasingly powerful branding and promotion opportunity. In addition, institutions lacking oversight of consumer-review sites such as Yelp, where any angry consumer can rant publicly, are essentially waving a white flag on damage control.

Plus, with a Jobvite survey reporting that 92 percent of hiring managers use social media to recruit, the remaining 8 percent are missing the chance to attract top talent.

It wasn't long ago that Kaysha Kalkofen and JoAnna Dettman, cofounders of tSunela - a digital marketing firm with offices in Clayton, Mo., and Portland, Ore. - had a tough time selling clients on social media.

"You want me to be on Facebook?" was a fairly typical response to the suggestion that a company integrate social media into its marketing strategy, they said.

A megasecond in cyberspace later, rare is the corporation, small business, or nonprofit without a presence on Facebook, Twitter, LinkedIn, YouTube, and other prominent sites. Their objective is the most basic lesson learned in Marketing 101.

But experts say a successful social-media strategy involves far more than just getting your company's name out there.

Health-care institutions, for example, need to ensure that posts don't violate federal regulations protecting patient privacy.

Bound by compliance statutes, the financial-service sector is another industry that must adhere to strict standards on social-media sites.

With the need to follow ethics rules, Wells Fargo Advisors in St. Louis takes its cues from fellow financial institutions in the gradual roll-out of a presence on Facebook, Twitter, and LinkedIn.

"This is one place where we're happy to be a follower," chief marketing officer Chris Moloney said.

Above all, training for financial planners and brokers stresses that Securities and Exchange Commission rules that guide telephone, computer, and mail transactions are to be applied to social media, too.

"We have to tread very carefully about what [financial advisers] are allowed to say," said Jeff Leonard, vice president of digital-marketing strategy.

Proceeding with caution is key to navigating the landscape, Nicholls said. The author, who lives in London, said companies should adopt clear guidelines.

It's critical, he added, that employees understand comments communicated via social media will be closely monitored.

Because the personal can instantly become public on social media, Nicholls urged businesses to drive home the point that, right or wrong, employees' comments on Facebook or Twitter are often seen as reflecting the viewpoint of their employers.

Companies may have the capability to rein in employees' public comments, but the First Amendment renders them powerless to stop online criticism lobbed by disgruntled customers and clients.

"If you're a good company, then social media will not necessarily make a great company," Nicholls said. "But if you are not a particularly good company, social media will amplify what you are. It will tell you things you may not want to hear."

Kalkofen said she counsels tSunela's clients to audit public comments and advises strongly against return attacks. "We recommend responding, but respond politely," she said. "Don't rant back at them."