This discussion is very well-laid out and thoughtful, and it got me thinking about terminology. I think every library will have a different priority for naming their constituents - but the decision should be deliberate and thoughtful.
"Member" may seem like a strange choice, but to me it is the most accurate representation of our population. We have a very distinct group we have been charged to serve. All staff, faculty, and students are automatically members of the library. Additionally, alumni from our institution are automatically members; they do have a separate set of needs and restrictions, so they would have a different membership group. Lastly, our friends of the library are paying members of the community that have elected membership for our services. Of course, each university has a different charge and may have different types of members yet mentioned.
A great example of corporate "membership" is Starbucks; anyone who shops at a Starbucks is a customer, just like anyone who never shops at Starbucks is a non-user (or some would argue, a consumer). There is a third group of Starbucks "members" that has an account associated with their patronage. Every time members visit the store they can pay with their mobile app, which is an added convenience, but it also allows the store to personalize deals and promotions to certain types of users. For example, I typically like to drink my home-brewed morning coffee on my commute to work, but sometimes will stop into Starbucks for an afternoon pick-me-up. Starbucks knows this behavior, and emails me promotions for happy hour specials, half priced drinks, or other non-morning specials that help get me back in the door.
While we will not be able to personalize services to that level, we can learn more about expected behavior by classifying our members into useful subgroups. Everyone that is in our community is automatically a member. However - each member can fall into the category of user or non-user. Users can be broken down using widely accepted marketing terminology of Heavy-Medium-Light (H/M/L) users. Non-users can be broken down into different categories like "financial support only," "non-local alumni," "actively enrolled students." All of a sudden I have created a segmentation analysis based on each individual's relationship with the library. This segmentation is more informative than "student, faculty, staff, alumni, friend," but is still not debilitating or bloated. I do not have to create a custom marketing solution for each of our members, but I can target specific groups based on this breakdown.
For example, we may try to increase use from our L-users by advertising in the library or on the library website. We know they are already existing users - we just have to give them a good reason to use the services more frequently. Surveying these students on program interests, academic needs, or learning styles can help us better connect with those individuals. The website would not be a good place to reach non-users, as they are unlikely to see those advertisements; partnering with other campus organizations or classroom outreach would be a much better strategy for non-users.
It can also help us design user-friendly websites. Having links that say, "new to the library" or "services for alumni" allows web visitors to self-direct to the most helpful information particular to their individualized experience. This strategy can also help prevent website bloat; instead of having extraneous information or little used resources taking up valuable real estate on your home page, we can distribute that information into useful places online.
For example, I don't think anyone ever accesses a library's "policy" page, unless they are an LIS student or another extenuating circumstance. Alumni, for example, may have a hard time realizing that "policy" is where they should click to find out what services are available to them. They would easily identify "Alumni" as an appropriate link, and the library could then provide all of the valuable information needed as a subpage. This removes bulky and formal language from the webpage, facilitates a service to the alumni, and connect the individual to all of their member benefits.
What do you call your patron group? Is it an active or on-going discussion at your library?