Without any example of how they were implemented it would be impossible to tell you how to automate it. I can say that if any browser can display it, it is nothing more than HTML and Javascript. If you can figure out how it is implemented you can figure out how to detect it with Selenium.
For example, on this Google Group if I place my pointer over the red "POST REPLY" button a message appears below the button saying "Post reply". When I look at the DOM I see:
<div tabindex="0" role="button" class="GOXWDPBBOT GOXWDPBBB1"
aria-hidden="false" data-title="Post reply" aria-label="Post reply" aria-pressed="false">
<input type="text" tabindex="-1" role="presentation"
style="opacity: 0; height: 1px; width: 1px; z-index: -1; overflow: hidden; position: absolute;">
<span class="GOXWDPBBCU">Post reply</span>
</div>
When I float over the button I see the class of the div attribute changes to have 'GOXWDPBBOT-hover'. So if it has "div.GOXWDPBBOT-hover" and "div[data-title='Post reply']" then I know it is a button with the message "Post reply" showing to the user. So I would write Selenium code to hover over the element then confirm it has the class attribute 'GOXWDPBBOT-hover'.
How your site implements this feature depends on the library your application is using and how they used it.