There are also interesting efforts outside the “Spectra world” ;-) on mashups. Particularly, I like Mozilla Ubiquity because of two aspects: putting the user in control with a client-side approach and the interaction experiences. It is a very young project, but very promising. Just look at the prototypes and enjoy:
Cool! Isn't it? :D
Mozilla on mashups by Carlos Veira Lorenzo is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.