MailChimp’s Voice 

MailChimp has a very robust writing guide focused on voice and tone in multiple situations.  I particularly like how they handle the customer’s emotion in negative situations:
Failure Message

User: What went wrong? I really need to get this campaign out.

User’s Feelings: Confusion, Stress, Anger
Tips

-Offer a solution or next step.  

-Be straightforward.  Explain what is going on right away.  

-Be calm. Don’t use exclamation points or alarming words like “alert” or “immediately.”

-Be serious. Don’t joke around with people who are frustrated.

MailChimp:  We’re experiencing a problem at one of our data centers. Our engineers are on the case, and will have things back to normal shortly.
MailChimp’s full voice and tone guide can be found here.

Author: Jay Fisher

I'm a product guy focused on building great consumer experiences. Gathering quick feedback and building internal consensus by iteratively improving on minimally viable products. My background is in consumer products and finance, I greatly enjoy tackling the challenges involved in financial services and technical product management I love making new professional acquaintances. Reach out (public@jayfisher.info) if you want to talk technology, business, product management, or agile. View all posts by Jay Fisher