Hover defines the style element when you hover over it the mouse cursor.
What is css hover effects?
Hover helps to make the website design more interesting and encourage the user to obtain additional information on the topic links.
For example, when you hover the mouse cursor on one of the links on the page, it can change color, indicating that they can be clicked. Typically, these links are added to pages or in texts, so turning them, the user has learned more accurate information or passed to the page of a certain product to purchase.
The screenshot above shows an example of color change when you hover on a certain news.
Note: For smartphones and tablets using your finger instead of a computer mouse, it is impossible to put the cursor on the object without third party software.
Example css hover effects
Hover and gallery
So what is a hover okay, but it can be used not only to illuminate the text links.
You can use a :hover to create image galleries with full size pictures that are displayed only when the mouse is over the thumbnail.
All these methods help to make the website more modern and interesting, and the post is not to over saturate information, adding the links that the user can obtain additional information. And hover helps to focus the attention of readers on these references.