Let's say one user has a lot of reputation on SO but almost none on another website such as Super User, wouldn't it make sense to display either:
Something like an average of rep through all the websites
The rep on each websites
A badge-like image for each website meaning "more than 500rep, more than 1000 rep" etc
I think this would make sense because, for instance, reputation earned on Serverfault means that the person is knowledgeable about server-related things. So why not showcase that on Stackoverflow if this person asks/answer a question over there?
Also this might encourage people to post on all websites. I'm saying this because I'm mostly on SO, but I like the other initiatives. After a few month on SO I gained some rep and it feels painful to start all over again on another website, so I kind of not go over there a lot. I know this a silly way of thinking about rep and this is not the point of reputation but I'm sure I'm not the only one.
This is not vital, but I'd like to know you guys inputs about this.