I guess the authors point was that it since there isn't a deep integration, it doesn't provide value to Salesforce.com users. The question is, why should it if

I guess the authors point was that it since there isn't a deep integration, it doesn't provide value to Salesforce.com users. The question is, why should it if they're not the target customer? Specially recently, people have been acquisitions that get integrated (closed down) and are happy then the company is left alone (Tumblr).