Yeah, then you could track him down, stake out his house, and hope you could eventually garner enough evidence to make a little better case than "we're pretty sure this guy made some post on the Internet claiming he got bought good E." Then of course the judge would see a college student with a minor possession charge and throw him straight into a drug treatment program, probably without even bothering to get a conviction. In the process they might get a huge amount of flak for expending all this effort chasing down a nominally respectable member of society...
Or all the cops that would be involved in said hypothetical mission could, with the same amount of time/effort, go down to a spot in the ghetto and arrest a few dozen poor addicts or dealers, many probably with criminal records, and be able to claim they're cleaning up the neighborhood and making it safe.
But honestly, I think they're gonna go after the college students...