Alright so if users like to pin tabs in FireFox there is a very simple way to trigger the browsers tab highlighting. This is for when a user is in another opened tab and something has changed in a pinned tab it will be highlighted to notify the user of a change.  This can be a notification from Facebook or new Tweets from Twitter. To trigger the highlighting the browser is watching the title of the page for changes.  So to test this please see the following code.  I have code set up to change the title by attaching a random number to the previous title to mimic notifications being sent.  I did this using JavaScripts native setInterval so this change will occur every 2000 miliseconds (every two seconds).

So if this page is opened and the tab is pinned using FireFox and another tab is opened one can see the highlighting of the pinned tab occur within two seconds. Note: If one is on the tab when the title is updated there will not be any highlighting and this only works in FireFox.

VIEW DEMO