“It can boost its traffic, but the reality is that I believe Twitter may be peaking in terms of users,” he said. “The media monsoon has brought a ton of new users in, but fundamentally I believe that everyone who wants to publicly tweet is already doing so.”
Steve Rubel, senior VP-insights for Edelman Digital
Google, Microsoft’s Bing to Include Twitter in Search - Advertising Age - Digital
A bold guess, I have this gut feeling that he might be onto something.