What they've done is implemented "adult content" flagging and filtering capability. What does this mean to you?
Well, there's finally a reason, if you're an adult, to go in and set your birthdate (at least to something that resembles your birthday). I've set my birthdate, but I hide the year (yes, it's ridiculous that my complete birthdate might put me at risk of identity-theft, but that's more the responsibility of the crack
If you're regularly discussing topics that qualify as "adult content" (even if it's not explicit, you have the option of flagging your whole journal as "Adult Concepts" (which, by my definition includes sex, drinking, accounting and politics). If you're regularly posting explicit material, you can flag your whole journal to "Explicit Adult Content." In someone's infinite wisdom, LJ decided to put this setting at the bottom of the "Viewing Options" control page instead of on the profile page.
You can also mark your individual journal entries (currently on the web interface, but I expect clients will add this soon) that may be at an "older" rating than your average post.
What happens? Users with a registered age under 14 can't see "Adult Concepts" posts and users with a registered age under 18 can't see "Explicit Adult Content" posts. Users without an age will have to
You also have the option as an adult, if you wish, to set up your friends page to "collapse" (it's an automatic LJ-cut on the whole post) adult-rated items; a good thing if your company is spying on your web browsing.
I was going to flag my journal "Adult Concepts" but I just checked it out in a logged-out browser. The implementation is a bit ugly, and reading back through a few months of posts there is very little I've got that I'm worried about children reading. I have gone back and flagged some specific posts "Adult" but they're vastly outnumbered.
Let the wild-and-freaky posts flow! Just remember to mark them...