Sometimes, you have really long titles or sentences that are meant for summary purposes, and you only want them to take up one line in the layout.
Just add the truncate class to any element to have it truncated to one visual line in the layout and get appended ellipses.
You may also add the data-truncate=true attribute to make it expand when clicked.
Here's a truncated block of text that gets truncated to one line and expanded when clicked.