That's really a random bunch of stories in my feed. I can't believe I upvoted some of them. But hell, I'll trade the lot for a photo of RiderOfGiraffes doing just that.
I didn't know that as well, but it's a nice feature. More than once i later wished i had kept some bookmark of stories i found via HN. Now i'll just upvote more and save all the precious bits.
Looks like submitted = saved as well.
That's because submitted -> upvoted, and upvoted = saved.