Build a Website

If we know someone is going for trip at famous places like London for example.. I would ask my friend to buy me some meaningful merchandise from the Sherlock Holmes Museum. In return, i would give him/her extra buck as thank you. ;) Would it be interesting if we can build a portal where local people can share their going-places or wishlist. When they saw someone originated from their places wanted to go 'somewhere', they may send request to help them buy item from their wishlist. Then there are more features like to offer 'Thank you bucks', Local grouping, Chat and PM features etc.