At one of my previous places of employment, we are starting to really get into using web services because they allow us to transmit data between our system, strategic partners and affiliates. One example of this is a project that I worked on which allowed some of our strategic partners to insert potential leads directly in to our database. This information was then scrubbed against our current leads for duplication and a response was sent back to the partner regarding weither or not the lead was accepted. In addition to this, we did talk about developing another web service that will allowed affiliates or vendors to use some of our dynamic data on their websites. We planed to include product information as well as a search and comparison feature to help promote our products.
Other various examples of how we could integrate the use of web services into our current system include the idea of allowing affiliates the ability to check their current stats in real time, and possibly allowing others to private label our products and then turn our shopping cart process in to another web service.
In my personal opinion, web services have been dramatically changed how people and business interact on the web. In fact, web services have changed the internet dramatically from a presentation based network to a data transaction based network.