We spend a great deal of time ourselves online trying to find information, comparing and contrasting data from different web sites. A number of us are well used to using sites such as www.kayak.com to assist in checking out travel options.
Read an interesting piece on www.cazoodle.com. For now offering comparison shopping re electronic goods and apartment rental (in US).
Authors claim to be using the power of their semantic search engine to extract the relevant data from multiple sites to present detailed product purchasing options and comparisons. In presenting the apartment data they include very good mashups to present the locations. In the case of electronic goods still seems to me that there is a lot of scope for variation in the additional items e.g. additional memory for a camera. However, even allowing for this, certainly shows the power of applications which can process data presented on web sites – and that is a basic objective for web 3.0/ semantic web.