Twitter Inc (NYSE:TWTR) CEO Dick Costolo received harsh words from Brian O’Malley, a partner at venture capital firm Accel Partners, which owns Twitter shares. Sarah Frier and Brad Stone did a story on Bloomberg Businessweek about Twitter Inc’s new head of product Daniel Graf.

twitter Dick Costolo

Harsh words for CEO unjustified

Frier and Stone say that Graf’s biggest challenge would be to work with Costolo. Both of them noted that there was a lot of action that ultimately lead to COO Ali Rowghani exit from the company, says a report from Business Insider.

According to O’Malley, Costolo is responsible for the executive trouble, adding,”If someone’s gotten divorced once, you really don’t know who’s to blame … But if someone’s gotten divorced five times, there may be a pattern there.”

The comment, a harsh one, is unjustified as no one knows what happened behind the scenes that led the exit of Rowghani, as well as of other executives. Rowghani was supposed to be the man behind new products on Twitter, but he failed to take the firm’s mainstream success to a new level.

As far as Graf’s role in the organization is concerned, it appears he has not done much to improve product development at Twitter, says the report. He is more focused towards reorganization of the product team, and has shut down a few projects to improve focus.

Mobile expansion vital for Twitter

Twitter is focusing on expanding into international waters, which is critical for the company from a revenue point of view. Twitter draws over two-thirds of its user base from international markets, but the United States still contributes the most overall to its revenues.

Twitter mentioned that International brands have given positive feedback regarding its new products.  At present, the-micro blogging site offers multiple advertising platforms such as Promoted Video, objective-based campaigns and pricing (which is in Beta), the Tweet Activity Dashboard, Mobile App Promotion and TV Conversation Targeting.

Investors are watching the stock closely over the past couple of earnings reports to see emerging ad and user growth. For the second-quarter of the year, revenue for the company came in at $312 million in which advertising segment represented $277 million. Mobile advertising is an important segment for the company as it represents nearly 80% of total ad revenues.