Ok, I signed up for a Yahoo ID and that worked just fine.
Now I'm tgrying to get an App ID so I can use the Yahoo Traffic RSS API, and I click on the "Get App ID" button, and it take me to a login screen (even though I'm already logged in.)
Sorry about that. Our last update has a cookie bug that affects certain paths between the documentation and the App ID registration page, causing this infinite loop that you've noticed. We're busy working on a permanent fix for this.
In the meantime, the workaround is as follows:
1. Close your browser completely 2. Start your browser again 3. Visit https://developer.apps.yahoo.com/projects 4. Sign in when requested 5. Click the New Project button 6. Select the choice "Answers, GeoPlanet, Local, ...", then click Continue
You will now be on the App ID registration screen. At this point you could also get there by returning to the Traffic page, then clicking the Get an App ID button.