Use IVR hosting for an application that does not need highly integrated data base interoperability. An IVR application that provides recorded information based on key presses in a tree, like high volume political campaigns. "Call this number to receive an important message from our candidate!"

This is a great solution for an application that received short bursts of a large number of calls. In these cases the cost to maintain the telephone line resources can't be justified because the actual percentage of utilization of the phone assets is very small. Using hosted IVR that charges on a usage bases makes a lot of sense.

The challenge in using IVR hosting services is their programming tool limits and also a loose integration to your database. Generally these systems have a GUI based application tool for building simple applications very quickly that become cumbersome when applications become complicated. Many IVR hosting systems also support Voice XML which can handle more complex IVR Applications.

Database integration is a little tricky with these approaches. Most companies consider their data to be secure on their own network so when you start talking about moving their entire database of customers across the internet to another network that they don't control people get uncomfortable. Some of these companies will allow you to access your data over the internet directly, but now you are opening your whole database up to the internet. Not a comfortable choice either. In all cases it requires a lot of trust of a system designed to be automated and simple to use by everybody.