Tracking an offline campaign is very, very hard to do. I've seen people employee all types of tricks but mostly it comes down to special urls and people simply don't always use those. The most effective way to track a campaign is by using a discount or bonus code that gives the new visitor something for entering a tracking code -- of course if you don't sell anything (like a forum), this does very little.
In terms of how to do local advertising, that really depends on the forum. For ScubaBoard our site is based entirely around an activity that people can only do in the real world. There are thousands of shops that offer services/ equipment sales, thousands more resorts, charters and other companies all of whom can help promote our name. The industry also has numerous publications and has even been the subject of a few movies. Thus when we do local promotion it really does mean going traditional. In the past we've used everything from print ads in some of the smaller magazines to fliers for a very targeted group to stickers and giveaways for more massive branding. Right now I am developing a more serious offline campaign which includes an initial order of 10,000 promotional stickers. We will also be attending a few trade shows this year with a booth in order to promote the site in person to thousands of potential members. Tomorrow I'm attending a local event one of our clubs holds every month. I'm going to interact with users, get in the water and have a good time but there is certainly a promotional value in my time there as well (and in the banner they asked me to bring along).
For a site like this one where the user base is online mostly, targeting a campaign in the real world can be far harder. There are a few nice magazines that have decent circulation numbers and may be worth investing in, although most are already well versed with forum communities given that subscribing means finding the magazine in the first place. Finding success here really means thinking outside the box and employing a unique campaign to hunt down webmasters. This means going outside of the webmaster arena and trying to sort out who webmasters are -- if you can establish common interests you can target them in other mediums. This might mean attending a more general trade show as an exhibitor in order to draw in the webmasters who also attend. It could also mean doing promotion in local publications that may not be webmaster focused but cater to potential webmaster demographics. Stickers and giveaways may not seem as effective but given the mass proliferation of the Internet they certainly can work. In the area where I currently reside (Irvine/ Southern Orange County) we have offices for almost every major high tech company. Placing an ad in a weekly magazine would certainly get eyeballs from webmasters, the question of course is how many and at what cost.
As I've said a few times, any successful marketing campaign must include offline advertising at some point. Discovering the right way to do that really depends on the site and your ability to isolate potential visitors and target them. Tracking also requires a unique approach to get even basic values and sometimes even that isn't possible -- you just have to look at overall traffic flows and try to figure out if there is any correlation (of course correlation doesn't always mean causality). Even tracking online campaigns is hard to do completely although many advertisers think otherwise; people remember names, they come back later and they don't always do what you want them to do for your research purpose. Offline most advertising means branding and that often means higher costs or more out-of-the-box solutions, but that's the fun part.
