America Online has announced a new blogging service for teenagers. Red Blogs, which AOL unveiled Tuesday, allows teenagers and parents to select the level of privacy they want for their online diaries; a private blog can be kept locked. A semiprivate blog is locked to all but those who are invited to read it. And a public blog allows access to anybody on the Net. However, blogs of younger teenagers, those between 13 and 15, will be locked from general public viewing. Similarly, with semiprivate blogs, parents must approve the list of people invited to read the journals of younger teenagers.