Rowghani will join Twitter from the Walt Disney animation studio in March as chief financial officer.
According to research by Pingdom 1.2 billion tweets were sent in January up from just over one billion in December.
The figures confirm comments made by Twitter founder Evan Williams last month who has hit back at claims that usage of the microblogging service was falling.
Williams tweeted that "across all metrics that matter, yesterday (January 12) was Twitter's highest-usage day ever. (And today will be bigger)".
In a blog post Pingdom said that its research showed that Twitter as of December was averaging almost 40 million tweets per day, which is a significantly higher number than a few months previous.
The chart highlights quite clearly how 2009 was the year of explosive growth for Twitter. The last six months alone have seen the number of tweets being sent has more than doubled from around 400,000.
Looking further back to 2008 the number of tweets being sent was less than 50 million before it hit early 2009 when the number of tweets began to inexorably rise.
Williams responded last month to a number of blog posts including one on Mashable that said Twitter's US traffic grew by just 1.45% in December to 22.81 million unique visitors in December.
Pingdom said that January 2010 saw more tweets per day (39.5 million) than the whole of September 2008 and it predicts that if Twitter's current growth rate continues Twitter should hit around 1.4 billion tweets in February.