Today, I visited Stackoverflow to discover that I had lost reputation from the last time I had been there. I didn't have any new notifications of any sort and my history didn't show any downvotes or anything.. So I was completely perplexed..
Then, I was reading some stuff on Super User and found something I had answered. The question got moved from SO to SU along with my reputation I had gotten before(I had 3 upvotes+accepted before the move).
I propose that we have some sort of notification for when our answers get moved from one site to another, especially if it involves moving reputation along with it.