Slack, the chat app that's been the talk of the startup world for the last year thanks to its incredible growth, is in talks to raise another round of funding at a $2 billion valuation, according to a Bloomberg report.
The report didn't say how much Slack is seeking to raise.
If the report is accurate, it would mean Slack's value has doubled in the last six months or so--the company raised $120 million in October led by Kleiner Perkins Caufield and Byers and Google Ventures, at the time raising at a $1.12 billion valuation.
Founder Stewart Butterfield, who had previously sold Flickr to Yahoo in 2005, has become something of a celebrity in Silicon Valley thanks in no small part to the company's explosive growth. In early February, the company celebrated its 1st birthday with the announcement that it adds $1 million in new contracts every 11 days.
Butterfield recently admitted that the company's $1 billion+ valuation in its last round was somewhat arbitrary, since investors were lining up to put money into the company and he thought $1 billion was a nice "psychological threshold" for customers, employees, and the press.
The app itself is a chat room for the workplace, aimed at reducing the amount of email coworkers send by making it super easy to have short and simple work conversations. Business Insider is a Slack customer, as are many other tech and media companies, with new customers signing on and getting started in droves. There are over 500,000 users on Slack and growing.
And for what it's worth, that number could be even higher: Fortune's Dan Primack tweeted today that he heard the number was closer to $2.5 billion.