‘Several year ago,’ Facebook Inc (NASDAQ:FB) had tried to buy Twitter Inc (NYSE:TWTR) for $500 million. Twitter co-founder Biz Stone said during an interview with Sky News that he, along with co-founder Evan Williams once traveled to meet Mark Zuckerberg. Neither of the microblogging site co-founders was interested in selling their startup. So, they decided to quote a price “so big that no one would ever say yes to it.”

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Twitter co-founder didn’t click with Zuckerberg

They decided to quote $500 million, and laughed at the price tag as they considered it boo big. Mark Zuckerberg did believe that it was a big number. However, later that day Facebook Inc (NASDAQ:FB) founder decided that Twitter Inc (NYSE:TWTR) was worth it, and he proposed to buy the startup for $500 million. However, Twitter co-founders Stone and Williams rejected the bid, saying that they were “just getting started” with the business.

It turned out to be a smart move. Twitter Inc (NYSE:TWTR) is currently valued at more than $23 billion after going public on the New York Stock Exchange last year. However, the stock has seen its price tumble from $73 in late December to less than $40 today. Stone said another reason they rejected the offer was that he “didn’t click” with Facebook Inc (NASDAQ:FB) founder. The sum of $500 million seems to be a bargain considering Facebook acquired WhatsApp for $19 billion and offered to buy Snapchat for $3 billion.

Twitter trying to revive slowing user growth

Biz Stone left Twitter Inc (NYSE:TWTR) in 2011. He has launched a new question-and-answer startup Jelly. Stone says the platform allows people to help one another by crowd-sourcing queries that Google Inc (NASDAQ:GOOGL) (NASDAQ:GOOG) can’t handle. Of late, Twitter has been struggling with slowing user growth, which has sparked concerns among investors. The company is trying to address the issue by launching new features and improving its user interface to make it more friendly to new users.

Twitter Inc (NYSE:TWTR) shares were down 0.41% to $39.08 at 11:14 AM EDT on Monday.