>I never see the Reddit mobile site and never need to tell the browser to request the desktop mode.
There is a seemingly persistent bug where reddit fails to remember preferences surrounding mobile/desktop and old/redesign. Sometimes you will click a link and the page it delivers you to will be on the mobile site, sometimes it will take you to the redesign. It's been going on for at least a year. I use reddit a lot and I run into it at least every week. Sometimes it sticks and I have to relog to get my preferences back.
Aside from Rich Integration (which is arguably also there if you include bots/scripting), most IRC clients have search, history, emoji, and reminders. What's missing I think is a pretty UI and lots of marketing.
I only used linked in as a resume i could refer people to and occasionally for networking with other professionals. what linkedin actually became is a way to get tons of unsolicited offers from headhunters and the resume component lost significant value because of that. I deleted my profile but there's no undoing it because of thoroughly it got crawled. I regret using it.
whatever new system comes it better have stronger privacy controls and more free form resumes.
Just about every Human Computer Interaction focused computer scientist I know is adamant that touch screens are inappropriate and vastly sub-optimal for many of the purposes it is currently employed in.
I don't think it's that researchers think it's good. I think that executives and programmers do.