Pistoff
For starters, I dislike using the term "cult." It's been my experience that most conversations on the subject tell me more about the people talking than they do about cults. Everybody's idea of a "cult" translated as "people who think differenly than I do." I prefer to talk about "high control groups" or "toxic societies" as these terms are more descriptive or what a group does.
Having said that, to answer your question the big identifier is look at what actions are incorporated into the structure of the group. In the case of JW's, disfellowshipping, shunning and the sanctions against asking questions or holding different opinions are integrated into the official structure of the organization. Most of the elder's manual is devoted to discussion of these issues. At the same time, there are no tangible benefits to being a JW; and a lot of tangible disadvantages, such as seperation from the community and no higher education.
Shunning and removing people are not integrated into the structure of AA, although some individuals can still be control freaks. I tell people not to judge AA by one or two groups, to shop around some and find one that suits them. The odds are not good with any treatment program, but there are still a lot of people like me around, who have benefited from the program.
Personally, I see a world of difference between AA and the Watchtower.