Google waves embedded
h3manth.com
h3manth.com
The whole concept is great, but their delivery failed. I am sure there always will be niche users who love wave and use it often but doubt it will ever have anywhere close to wide adoption like email.
Just opening that page causes Safari to hang for quite a while, and memory use to shoot up from ~40M to ~670M. That's not even close to being acceptable.
The actual wave client performs pretty well now.
I was at a friend's house for brunch today and mentioned the embedded Wave feature to another non-technical friend who has a very plain web site - this would be perfect for people like him: no change required in using cheap hosting.
Wave is also yet another platform for developers of web services (via Wave Robots), and I think that this will be another 'killer feature.'