They boast 17 million adoptions in 15 years of existence, which is no small feat. Consider that each adoption frees up an additional spot at a rescue that gives another animal a chance to get adopted and the numbers really start becoming astounding.
I'm inspired by their mission and have been (and will continue) to tweet adoptable senior pups from Petfinder.com's site every week. This will include a mix of both local pets, as well as those from a random city. Write a comment with city's that you'd like to see covered in the coming weeks and I'll add them to the queue. For good measure, throw in a blurb about why your city is a great place to own a pet. This is not restricted to the US, so if I have to find other resources to get time for international pets, don't worry, I'll find a way.