Millennials can be defined as people who reach adulthood in the early 2000's. That is a fairly broad definition but you could also call them people at or around early 30s and younger adults.
I have witnessed the characteristics of many different generations, including the "great generation," baby boomers, Gen X, and millennials. I am a boomer myself so I can communicate easily with those peers. I have, however, found the people who fit into the millennials a bit more different from me than most other generational groups. They have a whole set of rules that are different from most of the others I have mentioned and I mean this in a good way.
Getting along with all generations is essential for business success. I am very fortunate to have many millennials at the company I work for, WTWH Media. In the two years that I have been hear, I can say that I learned a great deal about millennials and I consider all of them my friends. It is all good.
Many of the people I deal with outside of my company are of the millennial age group too. Having an understanding of the generational differences has really helped me to understand and get along just great with all generations, including millennials. If you are in business and need to communicate with people of other generations, I suggest that you try to understand where people are coming from first and then proceed very patiently to establish common ground.
An individual should "act their age" and by this I mean, you don't have to be a millennial to not only interact with them but to really get along. Breaking the generational gaps has always been a challenge in business. It is probably even a little more challenging now.
Reach across the gap no matter which side you are on and it will benefit you in many ways.