Many people expect online communications — especially in “social” settings — to be immediate / synchronous.
The bar is being set by those who engage in seemingly real time. My view on customer service has largely been reset because of companies like Comcast (a brand I “hate” (hyperbole), but whose online customer service I love), UPS, Zappos and Amazon who effectively monitor activity streams coming out of tools like Twitter, set up Google Alerts, etc, and respond to your complaint or concern that wasn’t even directed specifically to them with a real person willing to help you, right then and there, through the medium itself.
For example, I think Comcast is an “evil company” (hyperbole) but it hardly matters because when I had a problem with my Comcast service and complained about it openly “@Comcast_Bonnie” replied to my tweet within minutes — someone I didn’t follow or know about, and asked me for more details. They began to engage.
It’s not just companies either. I tend to seek people in my “personal learning network (PLN)” who, like me, tend to engage more. When I have questions, I’d rather get answers from the experts themselves *when* I need them — otherwise I might as well hit Google.