Hi Allen.
Thanks for flagging this. What you’ve got there is a really, really old URL that apparently we didn’t update to point to the CDN, probably since years ago. I’ll update it to pass through platform.twitter.com instead.
As for what it’s doing: The current implementation of Web Intent Events maintains support for older versions of Internet Explorer using a Flash object to pass messages between windows (newer browsers just have window.postMessage. So, ft.swf is just a messaging bridge. As per my blog post from a few months ago, we’ll be retiring that code in the near-ish future and dropping Events support in IE7, in favour of a more robust and stable implementation.
Ben
