"Facebook Messenger wants to kill the phone number, but I'm not putting it on my resume or scheduling a meeting with my colleague on it," Cohn said. "So how do you get the phone number in the workflow? SMS is super relevant when you're meeting people, even professional contacts. People just sort of default to texting people you give your business card to these days."
To be sure, while Burner removes the "uncrossable line" of giving out your personal phone number to outside contacts, it doesn't solve the privacy issues of those worrying their boss will see their personal communications — a big concern for workers, according to research by the Society of Human Resource Management.
Still, Burner is one of several apps looking to build on the phone number the way that operating systems have expanded the reach of messaging apps. A similar app, Flyp, is one of the most popular apps featured on small business community platform Manta. In the future, Cohn said he sees professionals who often carry two separate phones for home and work, like attorneys, police officers and reporters, taking advantage of the privacy afforded by a semi-permanent phone number.
He already has one convert. Vocal venture capitalist Fred Wilson, who has written about the inconvenience of carrying multiple phones, recently asked conference attendees to text him (at a Burner number) their email addresses so he could send them updates.
"We're bridging a little bit of both worlds," Cohn said. "Everyone should practice safe text."
Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."