Google expects that when a user searches for a phrase and then clicks on your site, the user will be able to find the text that the user searched for. That means that any text that has keywords in it should be shown to all users without requiring interaction on the page.
In addition to incurring a specific penalty assessed by Google if they detect "hidden text", users tend to back out of your site when they don't find what they are looking for. Your rankings will fall drastically for any query where users bounce back to Google and look for something else. Google measures the "return to SERPs" and will de-rank pages that don't do well on this metric for a search term.
- Drop down menus: hidden menu text by default, but exposed on mouse-over
- Tool tips: exposed when a user mouses over an element
- Tabs: exposed when user clicks on the tab
These techniques are generally fine with Google, regardless of the specific technique used to initially hide the text. Just be careful not to put keyword rich text into anything that is initially hidden.