Just got the bad news from another session at MIX10 in Las Vegas: There won't be any copy-paste action going on, at least at first, as apps are going to be pretty well sandboxed.
That's the long and short of it. Whether you really need copy and paste is one of those things that'll be debating until the end of time -- or at least until it actually comes to WP7S. So strap in, everybody. It's gonna be a long ride.
Also gleaned from this afternoon's sessions is that despite Silverlight crawling all over the operating system, it won't actually be baked into Internet Explorer. That means you won't be able to take advantage of the usual Silverlight fodder you find online.