LOS ANGELES - Welcome to the blogosphere, chief. And "good luck with your cesspool of crime, disease and victimhood."

Such was top Los Angeles cop William J. Bratton's introduction to the rough-and-tumble world of online bulletin boards following his inaugural posting on LAPDblog.org.

Just a week old, the site makes the Los Angeles department the biggest police force in the United States and one of the first worldwide to blog.

So far, the "cesspool" post notwithstanding, Bratton's message and responses to it have largely been positive. The site's 24,000 visitors see announcements for department events and recycled press releases.

The point is to build public trust by improving communication to create an online give-and-take, even when the taking smarts.

"We want to hear feedback," said Lt. Paul Vernon, who is helping to oversee LAPDblog.org. "We welcome them, however serious or tongue-in-cheek they are."

As long as posts aren't profane and do not attack specific officers, they will stay online, police promise.

In one small test of that openness, one poster jabbed Bratton for his frequent trips: "The best thing about your blog is you can post it while at an airport. That way no one will know you are out of town! "

Police from Karnataka, India, to Eden Prairie, Minn., have started blogs and say they are happy with the results. Visitors to LAPD's blog say candor from a historically tightlipped department will determine the site's success.

"To say `blogging' implies having a conversation with the public," said media critic Jeff Jarvis. "It will be very hard for them to do. What's going to happen when there's another controversy in L.A.? Are they going to get into deep conversation about Rodney King? I'd be surprised."

But Sean Bonner, whose online prodding helped inspire the blog's launch, said Los Angeles police need time to get used to a new medium.

"They're all brand new to blogs," said Bonner, the Los Angeles-based co-founder of metroblogging.com, a worldwide network of city blogs. "They've been calling me and asking questions. They want to do it right."