Differences between components and web services:
1. Once a component is purchased, it is owned by the user whereas the web service is always owned by the provider. This is significant because it means that the owner has no control over changes to the service – if it changes (or disappears) then this may have adverse consequences for the user. With components, however, the user decides when newer versions are to be used.
2. Payment for services is by utilization so that users don’t have to buy an expensive component that is only occasionally used.
3. Component interactions can use much more efficient protocols than web services so components are better suited to high throughput/performance applications.
4. There are widely-accepted standards for services against several competing standards for components so service inter-operability is (should be) much better.