What kind of visitor numbers/member numbers are you getting? Do you know where people are finding the site?
Most of the traffic generated has come from Google Adwords and testing ads for the embassy section. Next up is google organic, again, mostly for the embassy section. The rest are referrals from blogs/forums mainly to the Travel News section.
There isn't a lot of promotion as most people view this as something they might use while traveling as opposed to adding content in the city they already reside in. And, thus, there is very little word of mouth.
I have seen some people join from marketing efforts, especially people who are leaving for a trip, but end up not using the site. I have a rough idea as to why (usability) but it is not concrete enough for a radical change