Tooltips are a small tool on hover tips, it can explain some words in you posts, or add links, make the website more lively.
To install and activate the plugin, you will see a tooltip sub menu on admin panel.
After add keyword and tooltips, the tooltips will be added into your post.
You can add image,video, audio…, anything into your tooltips and it will shown as tooltip in your post.
Also they have a pro version wich have many amazing features, the single site license is only $9, the unlimited license is only $27, this is really very cheap. 🙂