There are several situations in web application programming where it is necessary to schedule events to happen in the future, outside of the request driven model. Some of the most common are these:

In several of my web applications now I've come to a sticking point when it comes to scheduling events. As far as I know this is always left up to the developer to arrange. Scheduling events is considered outside their remit. There are a few solutions I know of. I can't see why the frameworks shouldn't provide an API for scheduling tasks. This would have the advantage of being simple, integrated and portable, and it could negotiate to use the platform scheduler or fall back to spawning a daemon to dispatch events.