I spoke this morning with someone from a large medical conference who wanted to know if blogs might be a good addition to their meeting marketing mix (here's what a blog is). I've written a few articles about meeting blogs (here, here, and here), but here's the short version.
The plusses: Blogs are easy and free-to-very-cheap to set up. They can be on external sites, or integrated into your website. They can extend your reach beyond your usual mailing lists because they tend to get picked up by search engines (because they usually contain a lot of links and are linked to from other blogs). They also can boost your site traffic if integrated into your site. They provide an additional sponsorship opportunity. They are a great way to connect with your attendee base because they have a "voice," attitude, and personality that usually isn't present in public relations and marketing pieces. They also show your attendees that you're up on all the latest tech tools. They can be a way to extend your conference to non-attendees if you post writeups of sessions during the show, and provide a way to follow up with attendees afterward.
The minuses: They are a lot of work. To be effective, you have to post several times a week; daily is better. They can't be just a rehash of your other public relations/marketing efforts—readers won't come back if it's just the usual PR. The posts have to be provocative, thought-provoking, and insightful, and even amusing, if possible. Your blogger has to be careful of libel, slander, and all that good stuff (plus HIPPA for for medical meetings). Your blogger should be someone well-regarded in your specialty. Spammers also like blogs, and if you allow comments, you'll probably spend some time every day deleting spam from the comments area and trackbacks. You also have to monitor comments to make sure no one gets out of hand. (These two points can be eliminated if you don't allow comments.) They also won't replace anything you're currently doing to market your meeting.
I'm probably missing some stuff (I'm sure Rich could think of more), but those are the main points we talked about. Personally, I'd say, go for it, but only if you're willing to put in the time, thought, and energy to do it right. If done well, it will make your organization—and your conference—even more attractive to your attendees (if they're not early adapters of this technology, it might only be a hit with a few people, but why not be a hit with a few people? They have friends, too. And blogging is finally getting some traction, so you'd be ahead of the game for next time around). If not done well, it'd be a big waste of time and energy.