An issue Cindy addresses in her preprofessional technology for teachers class is the longevity and visibility of what we say on the Internet. Her point to future teachers is that the behaviors you describe online (.e.g., myspace) may be available for consideration by future employers (or parents if that thought is scarier).
An eSchool News article considers a similar issue and describes some similar examples (e.g., high school athletes bragging about drinking behavior). The message – be aware of your digital footprint.