Bruni wrote an article in the Times the other day about the true problem with college diversity. He writes that diversity is not just about creating racially and socioeconomically diverse student bodies, but about how to integrate students after matriculation. The issue, as he sees it, is that students self segregate naturally.
It would be great if colleges provided opportunities for greater communication and integration, as he suggests. But in my experience, self-segregation happens on a level outside of the university's control. Friendships are formed around fun and play; some students play with a lot of money, and some must play with less. Students segregate on the basis of what they can afford: those who can fly on a jet to Europe during spring break will do so and solidify their friendships. Those who cannot will not, and will solidify their friendships in other ways. Those who shop at luxury stores between classes will do so together. Those who cannot, or who do not care about such things, will not.
Friend groups form on the basis of value more than race. Value can easily come from one's race and ethnic background, which is why it's so easy to join a cultural organization on campus and feel a sense of unity. But value can also come from class, and often times it does so more and more, the higher one's socioeconomic class. A very wealthy black or asian student may share more values with a similarly wealthy white student, rather than with a poor student of the same race.
During my college career, there were few extracurricular groups that fully sponsored fun for its members. My a cappella group was one that did provide financing for students with need to go on international tours (one reason why I donate specifically to the group every year). Another similar a cappella group at Harvard also fully sponsors all of its singers to go on an annual summer worldwide tour. These groups are funded privately, and have a rich history, which is part of the reason why its members, all brought together through a shared value, their love of music and performance, have the unique opportunity to socialize equally.
This is all to say that Bruni is right in pointing out an issue, a lack of diversity within the university, but wrong about the cause or solution. Programming, discussion groups, or student centers may help slightly, but diversity of interaction between 18 year olds on the same campus is ultimately a class issue - an issue that starts for many students and their families long before the university comes into the picture, and which oftentimes the university can do little to solve.