As the title says here’s one way to have simple show and hide effect using just CSS and avoid JavaScript. Idea is to use some tag inside the link (for example bold, or span or what ever) which will hide it’s content in normal state and show in hover state. Mostly it’s used for creating interesting menu effects with some additional images.
So here’s basic example code, and a few ideas where you can also use this, for example i’ve used it Gunmetal free WordPress Theme, you can see the demo here.