Since Facebook became the modern focus group and Twitter the new town crier, companies have flocked to social media to find out what was being said about them online.

“The best companies are the ones who listen to their customers and use that strategically,’’ said Stephanie Newby, chief executive of Boston social data company Crimson Hexagon. “The ones that go under are the ones that stop.’’

Investors are apparently betting that Newby is right. On Tuesday, the company said it raised an additional $20 million in equity to finance its ongoing expansion.

Crimson Hexagon is one of a growing roster of data analytics companies helping businesses monitor social media to make sense of all the chatter. Among others, Cambridge-based marketing and sales company Hubspot has a tool that lets its customers track social media conversations, as does industry giant Salesforce.

The new funding comes after a period of record growth for Crimson Hexagon. The startup says it has outgrown its current headquarters in the Seaport and is eyeing a new building in Fort Point. Crimson Hexagon says its customer base has swelled 75 percent over the past year alone. It has 125 employees at three US offices and one in London.

Its customers include Starbucks, Microsoft, even Twitter itself. Newby said another customer, General Mills, removed artificial colors and flavoring from its cereals after customers voiced concerns about the additives on social media.

The new funding will allow the company to add at least 75 jobs. As the market for data analysis matures in the Asia Pacific region, Newby said, the funding will help develop a customer support hub in Singapore.

The funding round was led by Sageview Capital of Connecticut and brings Crimson Hexagon’s funding total to $37.5 million since it was co-founded by Harvard professor Gary King in 2008.

King developed a way to quantify unstructured data, like speech, while on a social sciences research trip to Africa gathering verbal autopsies for a medical study. He devised a way to analyze the stories he collected. The same technology is used by Crimson Hexagon to monitor what people are saying in public posts on social media.

Crimson Hexagon says its database of more than 850 billion Facebook, Twitter, and Tumblr posts is the largest repository of social media posts in the world. That database — expected to top 1 trillion posts by the end of 2016 — serves as a sort of public ledger, helping businesses get a handle on how they’re being talked about on social media.

In an e-mail, Samantha Ngo, a researcher at Forrester Research in Cambridge, said social listening platforms like Crimson Hexagon’s “cut through the noise’’ of social media to give real-time insights on what customers are saying about a service or product.

And with approximately 500 million tweets sent into the ether daily, it’s a lot of noise to cut through.

Globe correspondent Amanda Burke can be reached at amanda.burke@globe.com.