Authenticated RSS
While hacking our problem tool at work, I thought it might be cool to set up an RSS feed for each problem so that you can be notified when comments are added onto it.
The major problem I hit was that the system uses cookie-based logins, so it would be a security hole to leave it open. Then I realised that, because RSS is just XML over HTTP, standard HTTP authentication over SSL would be possible, and it turns out that some RSS readers do indeed support this.
Outside the intranet world, authenticated RSS could be used to provide customised content or alerting services.
