One of the most powerful aspects of mashups is taking similar data from competing websites and providing a single place to examine the content. In this round-up of the best new mashups we'll look at three apps that aggregate data from multiple services. One looks at location check-ins, another at shared photos and another mashes photos with information about where they were taken.
Popcarte is a service for consumers, taking their uploaded photo and turning it into a card of the customer's choosing, from postcards to invitations to thank you notes, to special occasions, and then mails it out worldwide. The Popcarte API lets developers integrate the service into their apps.