The traveler network looks awesome, but tough to use. What cities does Boston attract vastly more than it draws Bostonians there? What cities do San Franciscans

The traveler network looks awesome, but tough to use. What cities does Boston attract vastly more than it draws Bostonians there? What cities do San Franciscans go to significantly more than any other urbanites? I tried a similar thing at TripAdvisor, using data from the Cities I've Visited(tm) FB app. One of the interesting results was that folks who visited Yellowstone disproportionately visited Zanzibar, compared to everyone else. Both off-the-beaten-path parks, but still, it was fascinating to see data backing up the hunch.