It would be great if Emacs had modes for some of the social networks and walled gardens. Or if there was a mode that would allow users to post messages to these networks and services.
Run local, not cloud-based.
First on my list is LinkedIn. Not because I like it, but because it has a clunky interface for adding posts. It takes more effort than any of the other networks. And so an Emacs way to post on LinkedIn would save much time.
As far as I can tell, there is no way to easily post messages from Emacs to LinkedIn or LinkedIn Groups. However, something to watch is Weboob (web outside of browsers). This French community is currently offering modules to just under 130 web sites and web services.
This walled garden has a group for Emacs users, but AFAIK there is no such Google+ thingy for Emacs.
- Identi.ca (statusnet)
There is identica-mode.el, which I used intensely ever since it was published. Since December 2012, it no longer works, because identi.ca switched to Pump.io.
It does not look like Identica-mode author Gabriel Saldana has plans to revamp it.
There is the very complete twittering-mode.el. In the days that identi.ca posted to Twitter, it would suffice to create messages in identica-mode. The latter which was based on the former.