Bad mouthing by disgruntled employees writing bad reviews about their managers and employers.

Embracing transparency is not an option. It’s a necessity.

Today, Glassdoor operates sites under the company’s brand in 13 countries. In 2015, it received a $70 million investment by Google Capital, giving it a cool $1 billion valuation.

With its massive reach, companies quickly realized that online reviews about culture, compensation policies and interviewing tactics could cost them a competitive edge for securing new talent.

It’s a kind of phenomenon that happen when current and former employees post their thoughts about working at a specific company, and the employer finds that they’re soon scrambling to change policies in an effort to stay competitive in the war for talent.