Just an idea, but have you guys ever considered a monthly e-zine? I know it would be a much bigger undertaking as it would be a proper publication whereas a blog doesn't need to be so polished, but it would be a very attractive feature. It would be a very suitable medium for publishing articles based on all the "How To" topics mentioned previously, in addition to actual opinion pieces from travellers and traveler profiles etc. Also, it would attract advertising.
You could then post on Twitter with "On This Months E-Zine: etc etc" and net new users from there.
Same with Facebook.
Well, we do have a monthly newsletter. Maybe not the same as an ezine, but it does point to a lot of other areas of the site. To be honest, getting the content organised, laid out and published each month would be a lot of work for our small team And we've never been big on chasing advertisers. But hey, if we get some good success with the blog, then you never know. Any urges to submit an article?