Migrants to IJ, 2007

The problem with "Adult concepts" (or either tag) is that people who are logged out--or who haven't given LJ their birthday--will see NOTHING of your entry except "this entry may contain adult concepts." No initial explanation, no stuff outside your cut tags. No way to warn them if this is a long entry or full of squicky stuff they might not want to read at work.

In fact, the whole "may contain adult concepts" tag may make people's jobs think twice about LJ access at all.

Unless you post stuff that minors are not legally allowed to see (and we have no laws that separate 13-year-olds from other minors, in terms of content), there's no reason to use the flagging at all. And minors are allowed to see pretty much everything except certain types of sexual IMAGES. (Text, they can see any of.)