[waterside81]

A monetization strategy for you: Try to associate any mentions of hotels, day trips, activities etc. with a link to viator/hotels.com etc. and get the referral fee.

If I was doing an idea like this, I think I would have gone mobile first (perhaps you're thinking to go that way anyway?) That way you can tap into people's geo location right away, easily associate photos & videos with the location, people can log their thoughts/feelings with a quick note, and perhaps purposely limit it to 140 to make it tweetable.