In response to a query from John B
Interesting topic for sure. I don't really have any data about Allston, so whatever I say is based on anecdotal evidence. I found relations between the students and the other residents to be mostly harmonious, although there's definitely sort of a sense that actual human interaction is to be avoided. This is not really stated by anyone, but it's an unwritten rule. When you see people on the street who are maybe hispanic, brazilian, or older asian people, you both ignore each other mostly, I think. It's basically respectful, but you're really acting like the other person is not there. In that way there are two separate worlds. People don't mix too much. Each group has its own stores and its own gathering places. The places that the groups have in common are probably limited to liquor stores, fast food joints, thrift stores (sometimes), and some ethnic restaurants where students might interact with the mostly immigrant community.
It's also interesting that while the students are certainly better off financially in comparison to the immigrants, they are also mostly interested in living on the cheap. There's definitely a certain type of person who is drawn to the neighborhood, usually more thrifty types among students. This may be a large part of the appeal of Allston; it's relatively cheap for Boston, and by taking advantage of some of the institutions that the immigrant communities have brought with them (cheaper ethnic restaurants, laundries, and groceries) students can save money. I also think that the privileged type of person that you find at BU, for example, might consider living in Allston something of an adventure. It offers cheaper living, ethnic flavor, and something of an art and music scene, plenty of bars, without the dangerous, violent urban side that places like Roxbury and Dorchester have. It makes you feel like you're "slumming it" in relative safety. And if you ever get tired of Allston, there's also Brookline right nearby, which is comparatively white and affluent, and probably even safer than Allston.
I do think, though that a lot of the students (and to a lesser extent, the immigrant community) don't give any respect to Allston as a place, precisely because they are usually not long-term residents. They are more likely to leave trash on the streets, break bottles at random, and make noise at night, because they sort of don't consider Allston a real place. It's just a place where the poor immigrants live and where people go to party and temporarily live cheaply during their college years. It is not, in this mindset, deserving of respect; it's not a 'real' neighborhood. I'm sure that this is also partially because people often come to Allston to visit the bars, and so are intoxicated. This is unpleasant for people like me (and I imagine for older, long-term residents), who just want to live quietly, go to work, and occasionally enjoy some of the many restaurants.
I hope that helps you some. Let me know if I can provide any more information, or if you want me to expand on any of these points.