Most productivity and communication apps have advanced features (e.g. keyboard shortcuts, advanced search etc) to allow users be use the tool more effectively, but they are not readily discoverable directly within the app.
A lot of apps rely on a "tips and tricks" section within their documentations or support site to capture this information. (e.g. HipChat) This means a user have to 1) know advanced features exist, 2) be motivated enough to navigate to the documentations to learn.
It makes sense not to clutter the interface with advanced features to make it easier for on-boarding new users, but, at the same time, is documentation outside the app the best approach for presenting these?
I noticed there is this post Discovering new features talking about getting users to try new features. I'm not sure Seductive Design applies in this case because these tend not to be different features per se, but ways to use parts of the system the user cares about more effectively.