This debate is interesting, but living near both a community college and a university, I can say that seeing an interracial couple (overwhelmingly a Black guy/white girl) is quite common - not 50/50 of every couple we see, but definitely in the vicinity of 75/25 (25% being interracial). Will these people get married? Donno. But it is very common among the 20-somethings. That's where I base my argument that for this generation (whatever letter you want to assign to it) it's more of a trend. I'm thinking that we are seeing a shift in perception, that race doesn't matter. You love who you love, regardless of skin color.
To reinforce the thought that it's becoming a trend, I point to Hollywood. Look at the commercials. How many do you see with an interracial couple. Of all the interracial couples, how many are Black guy/White girl? The majority. During an evening of watching broadcast television, we counted seven different commercials with interracial families. Of these, four were Black guy/White girl. It's becoming so common they're easy to miss! This advertising is further reinforcing the concept that 'it is okay to date outside your race' making it a trend.
The fad part comes in with older generations. They may dabble in interracial encounters, but for the vast majority, it's just a few times, with one or two lovers. But doing this has become more socially acceptable than 10 - 15 years ago. I'm sure having an affair (with husband's consent) with a Black guy back then was comparatively rare, especially WRT today. For these folks, it's not a long term thing, more of a fling, just to see what it was like. Hence the 'fad' label.