I believe another mind shift is developing in Social Media. Its the development of Social Service.
You cant assume on Twitter that the people who follow you are necessarily your customers.
In my mind Customer Service on Twitter/Facebook is a component of a Social Service. Social Service eliminates the requirement for the other person to have done business with you at all.
The proviso is; If you're apart of the community you deserve to receive the same level of service as anyone else.
Social Service is knowledge sharing and knowledge building, it's an opportunity to be in the ears and minds of your community well before they are ready to purchase or do business with you.
Its rapport building, developing a sub-conscious level of trust with you and the brand.
Your business is on show, where questions and comments are very public, your resolution and problem solving is critical to remedying your customers complaint and building trust with those watching your tweets.
What you share with the community about your product or service not only adds value to those who have already purchased from you but those who might do business with you in the future
Customer Service is factual, results driven, requires a timely action, it's usually one on one. Social Service is public, fun, sharing, community driven, still needs to be factual but doesn't have the pressure associated with it. Social Service might involved "Asking Twitter" for a crowdsourced answer, acknowledging that the crowd might and probably does know more about your product that you.
Does this thought change the way you think about tweeting? How do you reach out to current customers vs potential customers or just interested peeps?
Further Reading - Here is another post about Social Customer Service
Check out this video post from @Garyvee - Same concept just from a different angle