Did you know that the wildly popular web portal can be one of the most valuable tools in your PR campaign, particularly if you're looking for grassroots publicity targeted at certain cities or countries?

Craigslist is a giant community bulleting board, an almost entirely free classified ad service where you can buy, sell or give away just about anything. Started in the late 1990s by Craig Newmark, it began as a list only for San Francisco. But it became so popular that it's turned into 190 separate lists for people in all 50 states in the United States and 35 other countries. The more than 80 discussion forums are devoted to a wide variety of topics.

More than 10 million people use Craigslist each month, so you never know who might be reading. No one edits your posts, but you'll be kicked off the list if your message is obscene. You can't post identical messages to more than one city or category, but you can post a photo if you wish.

Most posts are live for only 30 days. Posts in the events and classes categories are live for only 14 days. Once a message expires, you can repost it again and again. That means that if you're advertising an event in December, you can start posting it as early as September, then keep reposting it whenever it expires.

Here's just a small sample of the types of things Publicity Hounds can post on Craigslist:

• Meetings, fund-raisers and information about volunteers for every kind of community group imaginable. These can include poker clubs and knitting circles, self-help groups, fraternal groups and service clubs.

• Classes, activities and demonstrations at schools, colleges, universities or government agencies

• Anything dealing with artwork, whether you're looking for models or giving away art you no longer want

• Political meetings, rallies, volunteer opportunities, fund-raisers and ranting

• Musicians who are cutting new CDs, searching for band members or looking for gigs

• Free tips from hospitals, health care agencies and doctors on everything from cholesterol to bird flu

• Employee awards, open houses, new products and services, promotions and other news at local companies

• Speaking engagements, book signings and other events hosted by authors, speakers and experts

• Questions and comments about where to find the best bar, supermarket or barber shop in a certain community

• What you're doing in your small business, such as products and service you're offering, or free classes you're giving

• Anything dealing with child care, from where to find a babysitter to the best nannies

Every post is free except if you're posting job listings at the New York, San Francisco and Los Angeles lists.

I've been posting my business events to Craigslist for a few months, and I found the site difficult to navigate at first.

The categories can also be confusing. So before you decide on a category you want to post to, call up the other posts in that category to see if those are the types of people you want to target with your message. If not, find a category that's a better fit.

You can post a photo, but only if it can be found somewhere else on the Internet.

If you plan to post numerous messages, it's a good idea to create your own account, which is free. Every time you log on, you'll see a color-coded chart that will tell you which posts are still live and which have expired.

I had to write about five or six different posts before I became familiar with how the whole thing works. Read the frequently asked questions before you begin, then have fun. Once you start posting, you'll be hooked.

Nancy Mills has met tremendous success posting her community events the last three years to the Los Angeles Craigslist and she's learned from her mistakes. Now, she shares her secrets, tips and helpful advice on how to navigate the Craigslist labyrinth, save time, and use the list in creative ways to get the maximum exposure possible for your product, service, cause or issue. See "How to Use Craigslist as a Global Publicity Tool."