I suspect I know why: I suspect it takes special software to detect iphones and do different things with them, but I spent the day surfing, and videosift is the only spot where I am frustrated.  I can't see videos (they work well at youtube), if I open comments, it only shows me some with no link to go to the rest no matter how I move about, and I tried to post a comment, got to the end of the laborious tapping and then was told "malformed comment submission".

If any of you experienced iphone users can tell me things I don't know that will make it better, I would really like that.  I spend a lot of time over the day sifting, and I was looking forward to being able to do it with freedom.  As it is, I don't even seem to be able to use videosift to get to youtube, where I can really watch the video.