In search for greater keyboard ergonomy and improved typing productivity, the CapsLock key seems to be taking place for not much use. Many programmers redefine it to become a modifier key. One popular habit: Vi users prefer to set it to Escape, while Emacs users to Control. What if one likes both?
Imagine you are hacking on a project, working on some file, and you would like to quickly open another file of the same project, located in a completely different and possibly nested subdirectory. How to do this efficiently in Emacs?
Emacs offers many functionalities natively; I routinely use it for writing, email, news, chat, programming, web browsing, image viewing, and much more. Sharing the same environment and the same keyboard shortcuts everywhere is good for productivity. However, what if one uses a standalone GTK application such as Chromium or Pidgin? Is it possible to share most of Emacs keyboard shortcuts there as well?
The jabber.el package provides an Emacs interface to the Jabber/XMPP chatting ecosystem. I use it regularly with Google Talk and other Jabber services.
The dired mode is an Emacs interface to the filesystem, enabling one to perform certain operations on multiple files. The dired mode can be combined with other Emacs goodies such as the search and replace tool into a powerful multi-file editing tool.