Ask HN: Do we really need real-time social networks?

Facebook and twitter have put a lot of engineering effort into making their services real-time. You get the notification of a like the second another person clicks the button. You see comments (almost) immediately after they are published. You get tweets immediately.

But is that needed? Won't it be nearly the same if things happened with 30 or 60 seconds delay? (apart from the chat, of course). Would such a delay be a deal-breaker?