Enterprise mashups are now ready for it's prime time. Industry analysts are expecting this technology to be picked up by 2009 and then peak at 2013.
Enterprise mashup can be divided into 3 segments or flavors - presentation mashup , data mashup and process mashup.SOA can be positioned well for last two segments.
Currently SOA composition is very much a wired model [ SCA or ESB ] but if we can allow user-level composition to pipe the different information sources in real-time, I think we are pretty close to enterprise mashup - Enterprise "Data" Mashup.
Few pure play vendors like Denodo, Kapow or JackBe are coming up with platform which can make it a reality. Sun's openESB or WSO2 [ open source ESB vendor ] even tried to provide such a solution based on their ESB offering.
Interesting presentation on enterprise data mashup - Enterprise data mashup introduction from denodo