At the Google meeting in Amsterdam, one of the most interesting fact about Wave for me was about Wave and e-mail. While it has always been said that Wave is "how we would build e-mail today", today Wave keeps its distance from e-mail.
Wave presents a different paradigm from e-mail and this paradigm needs to evolve. In order to do so, it needs to keep a distance because otherwise it is particularly the e-mail associated aspects that improve.
Lars and Stephanie explained that in an earlier incarnation, Wave did include much functionality with e-mail in mind but that proved to hinder rather then help the development of the Wave paradigm, so they binned it. Similar functionality may be added later and will probably be added by another party.
This is similar to what we do with MediaWiki, our approach is that Wave provides superior editing while MediaWiki provides superior publishing. Our challenge is to appreciate these different strengths and bring them together. As long as we do not need to touch the MediaWiki functionality, there is the easy upgrade path for Wikipedia that we seek.
Our challenge is to find ways in Wave to leave MediaWiki alone and interface and provide necessary functionality in Wave. Some things are still missing; internationalisation and localisations is crucial not only for the core product but also for the robots. The use of MediaWiki authentication and authorisation, including blocks, is crucial. As crucial is the availability of the Wave code so that we can play with the look and feel, add toolbars and add to the toolbars. The fun thing is that our use case provides the Wave developers with concrete challenges. It has already served to punch holes in some theories and help improve them.
All in all, Wave is awesome and it was wonderful and productive to meet in person.