To paraphrase my lawyer, sometimes companies can be very creative about what the standard "Proprietary Inventions and Information" agreement covers. And any advice I give can basically be summed up as "get your own lawyer early."
No, we totally appreciate your input here, and I think that you'll find that being Digg's first technical guy carries a lot of street cred. Your insight is appreciated. And, even though things may not be looking great for you now, I wouldn't be suprised if you did better for yourself the second time around.
Although on a cautionary note, I'd be careful what I post here, because it does tend to get picked up. Comments I've made got picked up by ValleyWag, and that's almost never a good thing.