Seems that Edinburgh follows where others lead. Though in reality just shows that similar things happen in different places.
http://sdbikecommuter.com has been going for a whole year.
"What do we want to see in 2010? First, we’d like to continue the great discussions and events that these forums have cultivated thus far. Second, we would like to bring more women riders into the discussions here. Third, we would like to encourage and have more discussions of riding with kids and cargo. Fourth, continue to have fun, geek out on bikes, meet other bike people, and bring folks into the fold by meeting them in real life and charming them into riding more and driving less."
http://sdbikecommuter.com/comments.php?DiscussionID=285
To encourage the second aim there's a poster -
They also do a Tweed Ride! (Edinburgh is planning a tartan version.)