Should tooltips be used on Text/Links?

Should we use tooltips on text/links? I see many frameworks like Foundation support tooltips on text but I don't know the reason why? I assumed text is self explanatory but I believe Foundation must have a good reason to have tooltips appear on text.

http://foundation.zurb.com/sites/docs/v/5.5.3/components/tooltips.html

What are some examples where one might need to use a tooltip on text/link?