I would say that our alumnae chapters focus on common interests within the context of our Five Point Programmatic Thrust and national and regional frameworks. Our membership demographics reveal the similar careers that Sorors tend to be in. So, generally speaking, alumnae chapters are likeminded and similarly situated women with Delta in our hearts and on our minds.
ETA: I now see what is meant by "common interests" in this thread. No, our alumnae chapters are not based on "common interests" in the sense that "if you are a college professor or like to sculpt, join this chapter." Whether people are eligible to join particular chapters is based on other factors.
On that note, Sorors who have similar interests often join certain committees and participate in certain programs. If you're a medical doctor, for instance, you may be interested in the Physical and Mental Health programmatic thrust and therefore join a committee and work with those programs/create programs. This works toward Delta and also for expanding your social and professional networks. Also, similar to what Drolefile stated, people who have similar interests beyond that can form their own book club, church-going groups, and other social and professional networks outside of the alumnae chapter. Wherever there are people, there will be associations (ETA: even if they aren't the formality of an "alumni association").
