I've got a functional-heavy web app for a closed number of users who tend to forget about some features, like shortcuts. I could periodically train them, but that's not a good way.
I'm wondering is it a good idea to show them some hints like "do you know that..." in a pop-up and how effective is it?
I don't want users to just dismiss them without reading the content.
Are there any other ways (other than writing docs, wikis etc.) to teach users the interface in a friendly way, so they would discover some things themeselves?