If you have a mobile version of your website (also based on Joomla!) and it isn’t responsive/adaptive you may want to provide a note to the users if that version is more appropriate.
Once you have spent the time buling mobile templates you probably want to make sure that your readers on smartphones see those designs. There are many ways how to detect mobile devices, some work better than others. This time I’ll present you a very simple CSS3 solution created by Ian Hansson (Twitter: @teapoted). If somebody will resize screen below 900px will see a note “Hey! We also have a mobile version” on the top of page.