Daily Digest: 9/18/07

The National Journal launches a political stock exchange, giving people the chance to predict the outcome of the election; yesterday was the original date of the Republican CNN/YouTube debate, and Katherine Seelye wonders if the idea has lost its steam; according to Hitwise, Fred Thompson's website is getting more traffic than anyone elses'; Hillary Clinton produces an "interactive webcast" to explain her health plan tonight; a new episode of "Running with Rudy" follows Rudy to a NASCAR track in New Hampshire; and Mitt Romney's campaign calls is create-your-own-ad contest a success.