I'm surprised he didn't mention integration with mobile. As more and more people moved their primary engagement with the internet to mobile, sites that were built for desktop got left behind. I guess you could file that under the "software sucks" category?

The chat box stuff is interesting. Never thought about it. Couldn't a chat thread simply be preserved as a regular thread on the forum though? While maintaining its fast paced and real time quality

I think another aspect to consider, relevant to SN, is just declining literacy in the population. I think young people people are less attracted to text based mediums