Unite is an interesting idea, letting non-techies easily share materials with friends and relatives. Opera provides an intermediary service: they map your account to whatever temporary IP address you have, deals with NATs, acting as a proxy between the web server running on your laptop and friends' and family members' browsers.
While I have been getting very interested in cloud computing in the last 6 months (using Amazon's and Google's offerings, and I spent an hour with someone at Sun yesterday giving them usability feedback on their soon to be released cloud services web interface), I am also interested in peer to peer systems. With some inter mediation, Unite is sort-of peer to peer (except for the reliance on an intermediate proxy service, although in some circumstances UPnP is used and no proxy is required). It is fine that Opera provides the back end services for Unite inter mediation. I would also like to see open source implementations (could be as simple as a little proxy server written in a scripting language and a Firefox plugin - if there is not already something like this, I expect to see some projects soon). For example, I might want to run my own intermediary service for friends and family. Anyway, ignoring the hype, I think that Unite is a good and also interesting idea.